Pan Dulce

The Bread
1 package dry yeast
3/4 cup warm water (105 f to 115 f)
3/4 cup sugar
3 tablespoons butter or margarine, melted
2 eggs, beaten
1/2 teaspoon salt
3 1/2 cups all-purpose flour

The Topping
1 cup sugar
1 cup all-purpose flour
1 teaspoon ground cinnamon
1/8 teaspoon salt
1/2 cup butter or margarine
1 egg yolk

Dissolve yeast in warm water in a large mixing bowl; let yeast mixture stand 5 minutes. Add 3/4 cup sugar, melted butter, 2 beaten eggs, and 1/2 teaspoon salt to yeast mixture, and beat at medium speed of an electric mixer until ingredients are well blended. Gradually add 3 1/2 cups flour, beating until mixture is smooth. (Dough will be sticky.) Place dough in a well-greased bowl, turning to grease top. Cover and let rise in a warm place (85'), free from drafts, 1 1/2 hours or until doubled in bulk.
Punch dough down; turn out onto a lightly floured surface, and knead until dough. is smooth and elastic (2 to 3 minutes). Shape dough into 18 balls, and place 2 inches apart on greased baking sheets. Flatten each ball slightly. Combine 1 cup sugar, 1 cup flour, ground cinnamon, and 1/8 teaspoon salt in a medium mixing bowl; cut in 1/2 cup butter with a pastry blender until mixture resembles coarse meal. Stir in egg yolk. Shape mixture into 18 balls; roll each ball to a 3-inch circle on a lightly floured surface. Using a metal spatula, place one circle on top of each roll. (Circles should completely cover the top of each roll.)
Score through topping and halfway through roll with a sharp knife, forming a swirl or a crisscross design. Cover and let rise in a warm place, free from drafts, 30 minutes or until doubled in bulk. Bake at 400f for 10 minutes or until lightly browned.