Preheat oven to 375 degrees Fahrenheit (190 degrees Celsius). Lightly spray a 7x11 casserole dish with cooking spray, and set aside.
In a large skillet set over medium heat, add the olive oil. When the oil is hot, add the beef and break it up. Add onions and seasonings, and cook until the beef is browned. Pour in 1/3 cup of enchilada sauce into the pan and stir to combine. Remove from heat and set aside.
Pour the remaining enchilada sauce into a pie dish. Coat the tortillas one at a time, then fill with beef and a sprinkle of cheese. Roll up and place into the prepared baking dish. Repeat until all of the filling is gone. You may need one or two more tortillas depending on how full you fill them.
Pour the leftover enchilada sauce over the top, then sprinkle with the remaining cheese, green onions, and olives.
Cover with aluminum foil and bake for 20 minutes, then remove the foil and continue baking for an additional 10 minutes.
Remove from the oven and let rest for 10 minutes before serving. Sprinkle with cilantro, if desired.
Notes
*I like to use a can of mild and a can of medium.**Frying the tortillas in an inch of canola oil makes them even more amazing—just make sure to pat any excess oil off.To STORE your leftover enchiladas, place them in an airtight container in the fridge, where they will stay fresh for up to 3 days. If you want to FREEZE them, wrap them tightly or use a freezer-safe container, and they will keep for up to 3 months.To REHEAT, thaw in the fridge overnight, then warm in a 350°F (175°C) oven for 20-25 minutes. You can also microwave individual portions for a quicker option.