Heat olive oil in a large saucepan over medium heat. Add onions and garlic, and cook until the onions become clear.
While the onions and garlic are cooking, gather all the seasoning and measure them out.
Add the tomato sauce, 3 cups of water, and all the seasoning to the saucepan. Bring the mixture to a boil, then reduce heat to low and let it simmer for 45 minutes. Stir the sauce every 15 minutes and add more water as needed. Aim for a thick and flavorful sauce.
Let the sauce cool for a bit. Preheat the oven to 350 degrees and spray a large pan with non-stick cooking spray.
Dip corn tortillas in the sauce, making sure to cover them well on each side. This will soften them and make them easier to roll.
Place a small amount of meat and cheese in the center of each tortilla.
Roll the tortillas and place them seam down in the pan.
When you have rolled the desired amount of enchiladas, top them with 1/2 cup of enchilada sauce per 11-12 enchiladas. Avoid using too much sauce, or the enchiladas will become soggy.
Optionally, add diced onions and 1 cup of shredded cheddar cheese per 11-12 enchiladas.
Bake the enchiladas covered for about 40 minutes.
Uncover the pan and bake for another 10 minutes.
Serve the enchiladas with rice and beans, and enjoy!