Solution: Starting with the cornerstone of cheesecake, that is, cream cheese, we tested fresh cream cheese, Philadelphia brand commercial cream cheese, Philadelphia's Neufchatel (one-third less fat), light (50 percent less fat), and no-fat cream cheeses. We found that the regular Philadelphia brand cream cheese baked up a superior cheesecake -- smooth and creamy. In testing eggs, we learned that a good cheesecake needs a combination of both whites and yolks. To get a light and airy style of cheesecake, though, it was key to whip the egg whites and fold them into the batter. The addition of cream gives a velvety, smooth texture, but too much of it and you begin to mask the cream cheese flavor. Sour cream supports the underlying tang of the cream cheese, but, if overdone, it takes over as the dominant flavor. You need a little of each -- cream for texture and sour cream for flavor. With our ingredients settled, we focused in on how to keep the cheesecake from baking up grainy and cracked. We were not surprised to find that a water bath protects a cake from harsh, direct heat that can cause it to overcook, crack, and sink. Finally, to get a smooth-textured, dense cheesecake we found that the unusual approach of starting with a high oven heat (500 degrees) and then lowering it to 200 degrees worked on two ends. The high heat nicely browned the graham cracker crust and caused the eggs to puff. The low heat gently cooked the cake through slowly dehydrating it so that it was dense yet creamy in texture.

RICH AND CREAMY CHEESECAKE

Serves 12 to 16

1 tablespoon unsalted butter, melted
3 tablespoons graham cracker crumbs
2 pounds cream cheese
1 1/4 cups sugar
4 large eggs
1 teaspoon zest from small lemon, minced
2 teaspoons vanilla extract
1/4 cup heavy cream
1/4 cup sour cream

1. Adjust oven rack to middle position and heat oven to 325 degrees. Line bottom of 9-inch springform pan with foil, tuck foil underneath pan bottom, assemble pan, then pull foil around side of pan. Brush bottom and sides with butter. Sprinkle crumbs over bottom. Tilt pan in all directions to coat evenly with crumbs. Cover pan underneath and along sides with sheet of heavy-duty foil and set in large roasting pan. Bring kettle of water to boil for water bath.

2. Meanwhile, beat cream cheese in bowl of electric mixer until smooth. Gradually add sugar and beat on medium speed until sugar dissolves, about 3 minutes. Add eggs, one at a time, beating until just incorporated and scraping down after each addition. (If you don't scrape down the bowl after each egg, cream cheese that sticks to the bowl will ultimately show up as lumps in the batter.) Add zest and vanilla and beat until just incorporated. Remove bowl from mixer; stir in cream and sour cream.

3. Pour batter into prepared pan. Set roasting pan on oven rack and pour enough boiling water to come about halfway up side of springform pan. Bake until perimeter of cake is set, but center jiggles like Jell-O when pan is tapped, 55 to 60 minutes. Turn off heat and leave oven door ajar, using a long-handled kitchen fork or spoon to hold it open for 1 hour longer. Remove springform pan from water bath and set on wire rack; cool to room temperature. Cover and refrigerate until chilled, at least 4 hours. (Can be refrigerated up to 4 days.)

LIGHT AND AIRY CHEESECAKE

Follow recipe for Rich and Creamy Cheesecake, separating eggs. Add yolks, rather than whole eggs, at instructed time. Continue with recipe, stirring in cream and sour cream. Beat egg whites to soft peaks. Fold whites into batter, pour into prepared pan, and bake, reducing cooking time to 45 to 50 minutes.

DENSE AND FIRM CHEESECAKE

Follow recipe for Rich and Creamy Cheesecake, disregarding instructions for water bath. Bake cake at 500 degrees for 10 minutes. Reduce oven temperature to 200 degrees (leave oven door open until oven temperature reduces). Bake until cheesecake perimeter is set but center jiggles like Jell-O when pan is tapped, about 1 hour longer. Continue with cooling instructions in basic recipe.