Step 1

Preheat oven to 350º F.

Step 2

Drizzle olive oil into bottom of 12-inch skillet over medium heat. Once warm, add a tortilla, one at a time, to the skillet. Cook until crisp on each side, remove from the skillet with tongs and set aside.

Step 3

Add beef and onions to the skillet and cook until completely browned. Remove from heat and drain away any drippings. Add garlic to the skillet and cook until fragrant.

Step 4

Spoon about 1/2 cup of enchilada sauce into the bottom of a 9x13 casserole dish that has been sprayed with olive oil or cooking spray. Spread enchilada sauce to coat the bottom of the casserole dish.

Step 5

Place 3 tortillas on top of the enchilada sauce, overlapping them slightly at the edges to make all 3 tortillas fit lengthwise. Ladle on additional enchilada sauce, about 1/2 cup. Layer on beef, onion and garlic mixture, making sure to spread mixture evenly over tortillas and enchilada sauce.

Step 6

Top with large dollops of sour cream and spread slightly. Sprinkle on a little of both cheeses.

Step 7

Repeat layering with 3 more tortillas, enchilada sauce, beef mixture, sour cream, and end with cheeses.

Step 8

Bake in oven until cheeses have melted, about 20 minutes.

Step 9

Serve warm.