Dissolve yeast and 2 tablespoons sugar in warm water, stirring well. Let stand 5 minutes or until bubbly. Add 3 cups flour; beat well. Cover and let rise in a warm place (85°), free from drafts, overnight.
Add 1/2 cup sugar, milk, eggs, butter, salt, raisins, and enough remaining flour to make a stiff dough.
Shape dough into a ball; place in a greased bowl, turning to grease top. Cover and repeat rising procedure 1 hour or until doubled in bulk. Punch dough down and turn out onto a lightly floured surface. Knead 5 minutes or until smooth and elastic. Cover and let dough rest 10 minutes.
Divide dough in half. Roll each half into a 13- x 9-inch rectangle. Place in 2 greased 13- x 9- x 2-inch baking pans. Sprinkle topping evenly over the 2 coffee cakes. Cover and repeat rising procedure 1 hour or until doubled in bulk. Bake at 350° for 30 to 35 minutes.