1. Preheat the oven to 375°F.

2. Heat a large heavy-bottomed pot with a lid over medium-high heat. Add 1 tablespoon olive oil, ground beef, diced onion, and 1 teaspoon salt. Cook for 5–8 minutes, breaking the beef apart, until fully browned. Transfer the beef mixture to a plate and set aside.

3. In the same pot, add the remaining 1 tablespoon olive oil, diced potatoes, and ½ teaspoon salt. Reduce heat to medium, cover, and cook for about 10 minutes, stirring often, until the potatoes are just fork-tender. Add a small splash of water if sticking occurs.

4. Return the cooked beef mixture to the pot. Stir in the garlic and chili powder and cook for about 1 minute, until fragrant.

5. Turn off the heat. Mix in the tomato sauce, Worcestershire sauce, mustard, and 1 cup of shredded cheese. Stir until evenly combined.

6. Lightly grease a 9×16-inch baking dish with cooking spray. Transfer the mixture into the dish and spread evenly. Top with the remaining 1 cup of cheese.

7. Cover with foil and bake for 15 minutes. Remove the foil and bake an additional 5–10 minutes, until the cheese is melted, bubbly, and lightly golden.

8. Let rest for a few minutes before serving.