This desert, a cross between cake and sweet bread, is often baked for Easter. Grease side and bottom of 2 (10 inch) tube pans. Prepare Topping;set aside. In a shallow, medium bowl, dissolve yeast in warm water. Add 1 Tbsp sugar and 1/2 cup flour; stir to combine. Cover; let stand in a warm place 5 to 10 minutes until foamy. Heat milk and butter or margarine in a small saucepan until melted. Let stand until mixture cools to warm. In a large bowl, beat eggs, egg yolks and remaining 1 cup sugar until pale and frothy. Add cooled milk mixture, salt and yeast mixture. Beat unil smooth. Gradually beat in 4 1/2 cups flour. Stir in enough remaining flour to make a soft dough. Turn out dough on a lightly floured surface. Knead dough into a soft, smooth dough. Divied dough in 1/2. Arrange 1 part dough in each greased pan. Cover with a damp cloth; let rise in a warm place, free from drafts, until doubled in bulk, about 2 hours. Preheat oven to 350 F. Lightly beat 2 egg whites in a small bosl until foamy. Brush beaten egg whites on top of dough. Evenly sprinkle Topping over dough. Bake 50 to 55 minutes or until a wooden pick inserte in centre comes out clean. Cool cakes in pans 3 to 4 minutes on racks. Turn out of pans; cool completely on racks. Frost with Powdered Sugar Icing if desired. Makes two (10 inch) cakes. Topping: In a small bowl, combine sugar, flour, and cinnamon. Using a pastry blender or 2 knives, cut in butter or margarine until mixture resembles coarse crumbs. Powdered Sugar Icing: 2 egg whites 1 1/2 cups sifted powdered sugar 1/2 tsp lemon juice In a medium bowl, beat egg whites until frothy. Gradually add powdered sugar, beating constantly. Beat 10 minutes or until glossy. Add lemon juice; beat 2 minutes or until icing stands up in soft peaks. Makes abou 1 1/4 cup icing.