Pre-heat oven to 325F. Lightly coat mini-muffin pans with vegetable oil cooking spray (Pam) Combine the cream cheese, sugar, and egg in a mixing bowl or in a food processor. When well mixed, beat in the sour cream, flour, and vanilla. Fill muffin tins almost to the top and bake for about 20 minutes. The filling will have puffed up a bit. Let cool in the pans for an hour and then refrigerate for a few hours. Remove from pans with a small flexible knife. Yields 24 1/4 cup cheesecakes. Flavor variations: Add juice of two limes. Add 2 tsp. Orange zest and 1 Tbsp. Orange liquer or essence. Add mini chocolate chips. Add fruit preserves or jam. Raspberry is especially nice. Garnish with fresh fruit and/or whipped cream.