In large stock pot mix together chili powder,flour,garlic powder, cumin, salt and pepper with the water. Whisk together and simmer on low for 2-3 hrs. stirring often.
Soften tortillas in oil and drain on paper towels. Place some of chili gravy in 9x13 greased casserole dish. Place handful of cheese and sprinkle of onion on each softened tortilla and roll up. Place in pan side by side. Cover with remaining gravy and more cheese. Bake at 350 for 20 mins. Recipe for chili gravy can be doubled to make larger batch. Enjoy.