When Barbara and Marc Slutsky of Highland Park, Ill., married, she never thought she would end up keeping kosher.

After all, Barbara was raised in a reform Jewish family on Staten Island, N.Y. "We were pretty assimilated," she recalled recently. "Keeping kosher wasn't in the fine print," and she knew nothing about kashrut, the Hebrew word for kosher.

Yet today she knows a lot about kashrut. The Slutskys switched to a kosher lifestyle when their children were small - about the time Marc and others founded Aitz Hayim, a "synagogue without walls," and the family agreed its acts should match its faith.

Having converted to a fully kosher kitchen in 1989, the Slutskys may have been ahead of the kosher curve. Jews who grew up in non-observant households and have made the change are driving a booming market. For them, keeping kosher is one way to align daily life with their faith.

Joan Nathan is the author of the forthcoming "The New American Cooking" (Knopf, $35) and a number of books on Jewish food, including the prize-winning "Jewish Cooking in America." She doesn't keep kosher herself, she said, but a cousin in France became kosher late in life.

"There's a lot more fundamentalism in America today, and the Jewish people who are fundamentalists are coming back to keeping kosher," she said. "I'm secular, and not strictly kosher. But I do understand why people do it: They may want the religious connection, or the historical connection, or both."

Sales of kosher foods have skyrocketed, with sales of more than $8.2 billion in 2004, up 15 percent from the year before. Many new products make it easier for Jews who want to follow regulations that are thousands of years old.

Keeping kosher means following rabbinical laws based on dietary rules laid out in the Torah (and also found in the Old Testament books of Deuteronomy and Leviticus). The rules are complex, but prohibit pork and shellfish. They insist on the humane slaughter of healthy animals. Because they bar dairy and meat at the same meal, keeping a strict kosher kitchen requires two sets of dishes and cooking equipment: one for dairy meals, one for meat meals.

For Barbara, it was a gradual transition.

"We started by buying kosher meats, then gradually started reading labels," she said. "I did resist at first; it wasn't where I was. Then, one night we had friends over and I made a shrimp dish. That night, Marc said, 'I wish you wouldn't make that again. I just think that's not where we should be.' "

Shrimp isn't on the list of kosher foods. Neither is lobster.

"I remember the last time I had lobster," Barbara said. "I was expecting our second child. Our first child was so young, she didn't know what I was eating, but we started talking about it, and I realized it wasn't the example I wanted to set."

So, she said, "what we ate, and how our family ate, began to be a reflection of our beliefs. My husband is really hard to buy gifts for, so one year my present was that I told him I was ready to buy a second set of dishes."

Dual sets of everything in the kitchen is only one part of keeping kosher. Another is finding the ingredients you need. Fortunately, that's getting easier as more and more kosher foods come to market.

Menachem Lubinsky of Lubicom Market Consulting in New York tracks them. Lubicom also produces the annual Kosher Fest, the world's largest showcase of kosher foods, with products from 29 countries and 44 states.

Lubinsky said a combination of factors has influenced the growth.

"The core group of people that subscribe to kosher is growing," Lubinsky said. "Also, many more religious groups, including Muslims, buy kosher foods than ever before. And kosher is becoming more popular with regular Americans, who feel the food is safer, cleaner and more humane."

Nearly 40 percent of the products displayed at the 2005 Fancy Food Show in New York in July bore kosher certification, reported Kosher Today, and now more than 90,000 kosher foods are available in groceries.

That makes keeping "ingredient kosher" easier, said Lise Stern, author of "How to Keep Kosher."

Someone keeping "ingredient kosher," she said, might "look at the label and read ingredients, and if there are no non-kosher ingredients, buy the product. Trader Joe's punjab choley chickpeas doesn't have the hechsher (the mark that certifies it as kosher; its literal translation from Hebrew is "ritual permit"); but there are no non-kosher ingredients."

Still, Stern said, a stricter kosher family "might not eat in my house because there are non-kosher-certified foods in my house."

Debbie and Adam Winick of Highland Park recently "decided to step it up a notch," Debbie said. The couple has kept two sets of dishes, but didn't keep separate cooking equipment until they moved into a new house in February. Now, at last, they have enough room for the two dishwashers and the extra equipment.

"When we moved, we decided to kasher everything," Debbie said. "It's a huge commitment from a food prep standpoint, but in the end, it doesn't feel like it's that much work. You only have to figure out the kosher brands at the supermarket once, then you remember. Getting everything set up is a huge task, but once it's set up, you don't have to worry about it."

The Winicks have three daughters under the age of 5, she said. They don't hold the children to rigorous observance of kashrut, and won't until the kids are school-aged.

"We keep kosher for two main reasons: We want to be consistent with our kids; they'll be going to a kosher school, and we want them to be able to have their friends over.

"And also, some of our friends keep kosher, and we want to be able to have them over as well."

"Traditionally in our family, breakfast is milk and dinner is meat," she said. "Lunch is usually one or the other, depending on what the kids want. I don't give the kids cheese and meat on the same plate, but if they want milk, I'm not going to make a big deal of it."

Yet precisely how the Winicks keep kosher will always be evolving, she said.

"When our rabbi came over to help us kasher the kitchen, he said, 'You have to keep kosher in a way that you're comfortable with, or you're not going to keep kosher.' "

Indeed, Nathan said, newcomers find their own ways to keep kosher.

"Since there are so many different kinds of Jews, and so many different ways to be Jewish, you have to find a way of being Jewish that feels comfortable," Nathan said. "But food is a way of connecting across all those levels, and it's a way of teaching.

"By making foods from the past, you're making a connection to the past and to the future."

This dish has been served for Rosh Hashanah in Marc Slutsky's family for many years. Though the recipe has many steps, it's well worth the effort.Making the fricassee the day before you need it and refrigerating it overnight lets you remove a great deal of the fat from the finished dish. It's typical feast food: very rich, a once-in-a-great-while treat.<B>Roux:½ cup vegetable oil4 yellow onions, chopped½ cup flourcup sweet paprikaMeatballs:2 pounds ground beef3 cloves garlic, chopped½ cup matzo meal, see note¼ cup ketchup2 tablespoons dried, minced onion1 teaspoon salt½ teaspoon freshly ground pepperChicken:2 tablespoons vegetable oil20 chicken wings, cut in half, tips discarded10 chicken drumsticks1 tablespoon sweet paprika2 cans (1 quart each) chicken broth or 2 quarts homemade chicken stock½ cup chopped fresh parsley</B>For the roux, heat the oil in a large skillet over medium-high heat; add onions. Cook, stirring occasionally, until they just begin to turn brown, about six minutes. Gradually stir in flour and paprika until smooth.Reduce heat to medium-low; cook, stirring often, until mixture turns red-dish brown, about 15 minutes. Transfer the roux to a medium bowl; set aside. Wipe the skillet clean with a paper towel.For the meatballs, stir together all ingredients in a large bowl; form by tablespoons into small meatballs. Brown meatballs in batches in the skillet over medium-high heat until brown on all sides, about six minutes per batch. Set aside on a paper towel to drain; wipe the skillet clean.For the chicken, heat the vegetable oil in the skillet over medium-high heat; sprinkle chicken with paprika. Brown the chicken in batches, about four minutes per side. (It is important not to overcook the chicken at this point or it will fall apart later.)Heat 1½ cans of the chicken broth to a boil in a Dutch oven over medium-high heat; reduce heat to a simmer. Stir in the roux slowly, stirring until combined; stir in the chicken and meatballs. (Add more broth or water, if needed, to just cover ingredients.)Heat to a boil over medium-high heat; reduce heat to a simmer; cook until chicken and meatballs are cooked through but not falling apart, about 40 minutes. Remove from heat; cool to room temperature 30 minutes. Transfer half of the mixture to a bowl (for faster chilling); cover the Dutch oven and bowl. Refrigerate about eight hours.Skim the fat from the fricassee. Return contents of bowl into Dutch oven; cook over medium-low heat until hot, about 20 minutes. Sprinkle with parsley.Makes 20 servings.<B>Note</B>: Matzo meal is sold in the kosher foods aisle of many supermarkets.<B>Nutrition information per serving: 336 calories, 57 percent of calories from fat, 21 g fat, 5 g saturated fat, 75 mg cholesterol, 10 g carbohydrates, 26 g protein, 530 mg sodium, 2 g fiber</B>

Barbara Slutsky adapted this vegetarian dish from a 1995 recipe in Bon Appetit.<B>2 tablespoons olive oil4 cloves garlic, chopped3 cans (14 ½ ounces each) vegetable broth1 bag (16 ounces) lentils1 pound potatoes, peeled, cut into ½-inch pieces1 bag (10 ounces) fresh baby spinach½ cup chopped fresh mintJuice and zest of 1 lemon¼ teaspoon ground red pepper½ teaspoon salt or more to tasteFreshly ground black pepper</B>Heat the olive oil in a large saucepan over medium-high heat; add the garlic. Cook, stirring, until fragrant, about 30 seconds. Add broth and lentils; heat to a boil. Reduce heat; cover. Cook eight minutes.Add potatoes; cook uncovered, stirring occasionally, until potatoes and lentils are just tender, about 18 minutes. Stir spinach into the hot mixture until wilted, about 1 minute.Stir in the mint, lemon juice, zest and red pepper. Taste for seasoning; stir in salt and black pepper to taste.Makes four servings.<B>Nutrition information per serving: 580 calories, 39 percent of calories from fat, 26 g fat, 6 g saturated fat, 65 mg cholesterol, 55 g carbohydrates, 35 g protein, 952 mg sodium, 17 g fiber</B>

Although called a kuchen, this is actually a tart with a sugar topping."There is a little debate whether I originally got this recipe from an aunt of Marc's or her daughter-in-law," said Barbara Slutsky. "I'm just glad I got it. It's delicious, light and quick. If this is to be served with a meat meal, I use the margarine. If it's to be served with a dairy or pareve meal, I use unsalted butter. Peaches, apples or blueberries also work well."<B>Tart:1½ cups flour1 stick (½ cup) unsalted pareve margarine or unsalted butter2 tablespoons confectioners' sugar15-20 Italian plums or 10 large dark plums, slicedTopping:½ cup granulated sugar¼ teaspoon ground cinnamon1½ tablespoons chilled unsalted pareve margarine or unsalted butter, diced</B>For pastry, place the flour, margarine and confectioners' sugar in a food processor; pulse until it becomes a sandy consistency, about 30 seconds. Press mixture into a greased 9- or 10-inch tart pan (with removable bottom) or 13-by-9-inch greased baking pan. Freeze 45 minutes or refrigerate at least two hours.Heat the oven to 375 degrees. Remove crust from freezer or refrigerator; place plum pieces on top of prepared crust in an attractive pattern.For topping, stir the sugar and cinnamon together in a small bowl; sprinkle evenly over plums. Dot with margarine. Bake until edges are golden brown and mixture is cooked through, about 50 minutes. Remove from oven; transfer to a rack. Cool about onehour.Makes 10 servings.<B>Nutrition information per serving: 225 calories, 44 percent of calories from fat, 11 g fat, 7 g saturated fat, 29 mg cholesterol, 29 g carbohydrates, 3 g protein, 6 mg sodium, 2 g fiber</B>