Dissolve yeast in warm water; stir in sugar, salt, and oil. Beat in 3 cups flour, then stir in rest of flour. Knead and put into greased bowl. Cover and let rise. Put into pan (do not grease pans). Precook crust for 10 minutes at 400 degrees and then add sauce and toppings, except for cheese. Return to oven at 375 degrees for approximately 15 minutes, then add cheese and return to oven until cheese melts. I like to use 1/2 Cheddar and 1/2 Mozzarella cheese.