Dissolve yeast in warm water about 10 minutes.
In large bowl, combine flour, oil, salt, sugar and yeast water mixture. Knead into ball. Cover and let rise about 30 minutes. Divide dough in 2 parts. Roll each into thin pizza crust on well floured surface.
If using prepared crusts follow package instructions.
Melt butter in sauce pan. Add salt, pepper, rosemary, garlic and flour. When bubbly, add milk. Heat just to boiling. Blend in cheese.
Place on pizza pan or stone and add sauce and toppings. Bake at 400° for 12-15 minutes.