In a large saucepan, cook onions and garlic in the olive oil until onions are clear on medium heat. Gather seasoning and measure them out while onions and garlic are cooking. Add tomato sauce, 3 cups of water, and all the seasoning. Bring to a boil and reduce heat to low. Simmer for 45 minutes adding more water as needed, stirring about every 15 minutes. I usually add 1- 2 more cups in the cooking process. At the end you should have a thick flavorful sauce. Allow sauce to cool a bit. Prepare a large pan by spraying it with non-stick cooking spray and preheat oven to 350 degrees. Dip corn tortillas in sauce making sure they covered well on each side. This will soften them a bit and make rolling easier. Place a small amount of meat and cheese in the center of the corn tortilla. Roll the tortilla and place it seam down in the pan. When you have made the desired amount of enchiladas top with 1/2 cup of enchilada sauce per 11-12 enchiladas. You can put more sauce but don't put too much or they will be soggy. Top with optional diced onions and 1 cup of shredded cheddar cheese per 11-12 enchiladas. Bake covered for about 40 min. Uncover and bake another 10 min. Serve with rice and beans and enjoy! Freeze any unused sauce in a covered container.