In small bowl, dissolve yeast in warm water and set aside. Grease or spray large bowl and set aside.
In large bowl mix sugar, shortening, salt and whisked eggs. Add 2 cups of flour and mix until smooth. Add yeast mixture. Mix in remaining flour until dough is easy to handle. Knead dough on lightly floured surface for 5 - 10 minutes. Place in well-greased bowl, cover with kitchen towel and let rise until doubled in size, usually 1 to 1 1/2 hours. When doubled in size, punch down dough. Roll out on a floured surface into an approximately 15 X 9-inch rectangle.
Spread dough rectangle with softened butter or margarine, sprinkle with granulated sugar and ground cinnamon. If desired, sprinkle with walnuts, pecans or raisins. Beginning at the 15-inch side, roll up dough and cut uneven ends off roll. Starting at the center of the roll, cut into equal portions, approximately 1 1/2 - 2 inches wide.
Spread remaining softened butter on bottom of baking pans (9X13 glass, pie plates or whatever you have). Sprinkle bottom of pan with brown sugar. Drizzle Karo light corn syrup over butter and brown sugar mixture in bottom of pan. Note: Mom usually made a huge batch and used every baking pan and platter in the house.
Place dough portions (pinwheels) down onto butter, brown sugar and Karo syrup close together in pans. Sides should be touching each other. Let rise to double in size, about 45 minutes. Bake in 350 degree oven for approximately 40 minutes. Tops will be browned and dough needs to be completely cooked but not dry.
Remove from oven and let cool about 5 minutes. Place serving platter or dish over the top of the pan the rolls were cooked in. Note: your serving platter or dish needs to be slightly larger (an inch or so) than the pan the rolls were cooked in to catch the syrup mixture. Grasp the sides firmly with hot pads or oven mitts. Flip baking pan and serving dish together away from you. Let syrup mixture drip down over the top and sides. Cool completely and serve.