Combine all shredded cheeses in a large bowl. Place half of the cheeses in a sprayed 13x9 pan. Layer jalapenos over cheese mixture and then top with remaining cheeses. Beat flour, eggs and evaporated milk til smooth. Spread over cheese mixture. Bake for 40-45 minutes. Let cool for about 20 minutes before cutting.
For variations I have added minced onion,crumbled bacon or ham.