Heat up olive oil and Chili Powder with 4 TBL Flour, Simmer for a few minutes Add Tomato Sauce, onion powder, salt and water and let cook for 5-10 minutes or until mixture begins to thicken. Use a stick blender on sauce if you want it to be smooth. Heat cooking oil in a pan and briefly fry each corn tortillas until lightly brown then drain on a cooling rack or paper towels. Ladle some of the sauce on the bottom of your roasting pan, then top with one layer of tortillas. Sprinkle with cheese, then pour more sauce on top. Repeat until you have completed all of your layers. Bake in a 350° oven for 20-30 minutes or until golden brown.