Combine 1-1/2 cups flour, undissolved yeast, sugar and salt in a large mixer bowl. Heat water, sour cream and butter until very warm (120° to 130°F). Gradually add to flour mixture. Beat 2 minutes at medium speed of electric mixer, scraping bowl occasionally. Add eggs and 1 cup flour; beat 2 minutes at high speed. Stir in remaining 2 cups flour to make a stiff batter. Cover tightly with plastic wrap; refrigerate 2 to 24 hours.
Remove dough from refrigerator. Divide into 24 equal pieces; shape each into a ball. Place balls on greased baking sheets 2 inches apart. Cover; let rest 15 minutes. Make a deep and wide indentation on each ball by pushing outward toward edge, leaving 1/2-inch ridge around outside. Fill with a heaping teaspoon of pastry filling. Cover with plastic wrap that has been sprayed with cooking spray. Let rise in warm, draft-free place until doubled in size, about 1 hour.
Bake in preheated 350°F oven for 18 to 23 minutes or until done. Remove from baking sheets; cool on wire racks.