- With the rack in the middle position, preheat the oven to 190 °C (375 °F).
- Brush the tortillas with half the oil and sprinkle with a mixture of 15 ml (1 tablespoon) of chili powder and 15 ml (1 tablespoon) of oregano. Season with salt and pepper. Place in tortilla molds (see note) and bake for about 9 minutes. Remove from oven, let cool for 5 minutes and unmould. Set aside.
- In a skillet, brown the onion in the butter and remaining oil for about 5 minutes. Add the garlic, beef, remaining chili powder and oregano, garlic salt and onion salt. Continue cooking, stirring until the meat is cooked. Season with pepper.
- Line each tortilla bowl with a bed of chopped lettuce. Add the meat and sprinkle with diced tomatoes, cilantro and cheese, then top with sour cream. Serve immediately.
The tortilla molds are small individual non-stick molds with fluted sides, about 14-cm (5-inch) tall sides and a base measuring approximately 7.5-cm (3-inch). They are found in good kitchen stores. You can’t find them? Use a large muffin pan. Your bowls will then be a little smaller.