Preheat oven to 350°F.
Add the oil to a large skillet over medium-high heat. When hot, add the onion and saute for 5-6 minutes until softened. Add the ground beef and spices, breaking up the meat and cooking until browned. Transfer meat to a bowl.
1 Tablespoon olive oil, 1 medium yellow onion, 1 pound ground beef, 1 Tablespoon chili powder, 1 teaspoon ground cumin, 1/2 teaspoon Kosher salt, 1/2 teaspoon dried oregano, 1/2 teaspoon garlic powder
Melt the butter for the sauce in the same pan. Whisk in the flour to form a roux and cook for 2 minutes. Whisk in all of the spices, then lowly whisk in the beef broth, a few splashes at a time to avoid lumps. Stir in the tomato sauce, then reduce the heat to a simmer and cook for 6-8 minutes, stirring frequently until slightly thickened.
3 Tablespoons salted butter, 1/4 cup all-purpose flour, 3 teaspoons chili powder, 1 teaspoon ground cumin, 1/2 teaspoon garlic powder, 1/2 teaspoon onion powder, 1/2 teaspoon smoked paprika, 1/2 teaspoon kosher salt, 1/2 teaspoon dried oregano, 1/4 teaspoon black pepper, 2 cups beef broth, 6 ounces tomato sauce
Mix 1/4 cup of each kind of cheese with the browned ground beef. Warm tortillas in the microwave wrapped in a damp paper towel until soft and pliable. Spread about 1/2 cup of the sauce in a thin layer on the bottom of a large 9x13-inch baking dish.
10-12 medium 8-inch [flour tortillas], 1 cup sharp cheddar cheese, 1 cup Monterey jack cheese
Fill each tortilla with about 1/3 cup of meat, then roll tightly and place seam-side down in the baking dish. Repeat until all the meat and tortillas have been used, then pour the remaining sauce over the enchiladas. Sprinkle with the rest of the cheese, then cover with aluminum foil.
Bake for 20-25 minutes, then remove the foil and cook for another 10-15 minutes until cheese is melted and the enchiladas are hot all the way through. Garnish with your favorite toppings and serve.
Freshly chopped cilantro leaves, Avocado, Tomato, Green onions, Olives, Sour cream