The crust: Stir together the dry crust ingredients.
Using a pastry cutter or two knives cut in the shortening until the mixture looks like crumbs.
Gently mix in the egg and milk--only mix gently until the mixture is just combined.
Turn out on a well floured board and knead the dough only 15 times.
Press evenly onto a greased 12" pizza pan.
Handle as little as possible.
In a skillet melt the butter over medium heat and cook the beef, mushrooms, garlic, oregano pepper, salt. and pepper. Break up the meat cook about 5 minutes or until the meat is browned and the mushrooms are cooked. Drain the meat well and put it on the biscuit crust.
Top with the salsa and cover with the cheese.
Bake in 450°F oven for approx 25 minutes or until the crust is golden and the cheese is all bubbly.