To make topping, combine cream cheese, 1/4 cup sugar, egg yolk, vanilla in a mixer and blend thoroughly. Set aside in refrigerator.
Heat sour cream in a saucepan on stovetop until warm. Stir in 1/2 cup sugar, salt and margarine and let cool. Dissolve yeast into warm water according to package directions and add to sour cream mixture. Add 2 eggs and flour then mix well. (Do not knead the dough.) Put dough in greased bowl, then cover and refrigerate overnight. Remove dough from the refrigerator and work into balls and place them in a pan. Flatten dough balls to 1/2-inch, grease with margarine and let dough rise for about 10 minutes. Make indentations in dough and add cream cheese topping, then top with 1 teaspoon strawberry preserves. Continue to let dough balls rise until they've doubled in size. Bake in a preheated 350 degree F oven for 25 minutes until they become lightly browned.
Recipe courtesy of Paige Smith