Dissolve yeast in warm water in a small bowl; let stand 5 minutes. Combine flour, 1/2 cup sugar, and salt in a large mixing bowl, stirring well. Combine sour cream, butter, and eggs, stirring well. Add dissolved yeast and sour cream mixture to dry ingredients. Beat at medium speed of a mixer 2 minutes or until smooth. Cover tightly, and chill 8 hours.
Divide dough in half; shape half of dough into 12 (2-inch) balls, smoothing out tops. Place 2 inches apart on a baking sheet coated with cooking spray. Repeat procedure with remaining dough. Cover and let rise 30 minutes or until doubled in bulk.
Preheat oven to 350°.
Bake rolls at 350° for 12 minutes or until very lightly browned. Let cool on wire racks.
Combine powdered sugar, cream cheese, and vanilla in a bowl; beat at medium speed of a mixer until smooth. Combine sugar sprinkles in a small bowl. Spread 2 teaspoons frosting on each roll. Sprinkle each roll with 3/8 teaspoon of sugar sprinkles.