Preparation - Heat oven to 400º. In a large mixing bowl, beat together Spam, eggs and milk. In a large skillet, melt butter; add egg mixture. Cook, to desired doneness, stirring often. Fill each tortilla with egg mixture and half of both kinds of cheese. . Roll up burrito and place seam side down in a 12" x 8" baking dish. Sprinkle burritos with remaining cheese. Bake 5 to 10 minutes or until cheese is melted and bubbly. Serve with salsa or taco sauce. Servers 4 to 6.