In a large skillet, brown the hamburger oven medium heat. Drain most of the fat, and return the pan to medium-low.
Stir in the flour and spices until the meat is well coated.
Add the milk, stirring while you pour.
Add the diced tomatoes, along with their juice, and let the mixture simmer until it thickens.
Tear up the tortillas and add them to the skillet.
Stir in the cheese until it melts, and serve!