In a large bowl, dissolve yeast in warm water. Stir in milk, 1/3 cup sugar, vegetable oil, Clabber Girl Baking Powder, salt, egg and 2 to 3 cups of the flour. Beat with mixer until smooth. By hand, mix in enough of the remaining flour to make the dough easy to handle. Turn dough onto well-floured surface; knead until smooth and elastic, about 10 minutes. Place in a greased bowl; turn greased side up. Cover, let rise in a warm place until double, about 1 1/2 hours (dough is ready if indentation remains when touched). Grease two 13x9x2-inch baking pans; set aside. Punch down dough; divide in half. Cover and let rest 10 minutes. Roll one half of the dough into a 12×10-inch rectangle. Spread with 2 tablespoons of the butter. Mix 1/2 cup sugar and the cinnamon. Sprinkle half of the cinnamon-sugar mixture over the rectangle. Sprinkle with half of the chopped nuts, if desired. Roll up, beginning at the 12-inch side. Pinch edge of the dough into the roll to seal. Stretch the roll to make it even. Cut the roll into twelve 1-inch slices. Place slightly apart in one of the baking pans. Wrap the pan tightly with heavy-duty aluminum foil. Let rise in warm place until double, about 30 minutes. Repeat with the remaining dough. Let rolls rise on countertop for 1/2 hour before refrigerating. Refrigerate 12 hours, but no longer than 48 hours. Next morning take rolls from refrigerator and let sit for about 1/2 hour before baking. To bake: Preheat oven to 350° F. Remove foil from pans. Bake at 350° F. for 30 to 35 minutes or until golden. Frost with powdered sugar frosting while warm. Makes 2 dozen rolls. Frosting: 1 cup powdered sugar, 1 Tablespoon milk, 1/2 teaspoon vanilla Mix powdered sugar, milk and vanilla until smooth and of spreading consistency. Frosts 1 pan of rolls.