Step 1: Preheat your oven to 350°F (175°C). Grease a medium-sized casserole dish lightly with oil or butter.

Step 2: In a large skillet, heat olive oil over medium heat. Add the chopped onion and garlic, and sauté until softened and fragrant, about 3–4 minutes.

Step 3: Add the ground beef to the skillet. Cook, breaking it up with a spatula, until fully browned and cooked through, about 7–8 minutes. Drain excess fat if necessary.

Step 4: Stir in the diced bell pepper, BBQ sauce, soy sauce, ground black pepper, salt, and red pepper flakes (if using). Cook for an additional 5 minutes, allowing the flavors to combine.

Step 5: Add the drained pineapple chunks into the beef mixture. Stir well to distribute the pineapple evenly throughout the beef.

Step 6: Transfer the beef mixture into your prepared casserole dish, spreading it out in an even layer.

Step 7: Sprinkle the shredded cheddar cheese over the top of the beef mixture.

Step 8: Bake in the preheated oven for 20–25 minutes, or until the cheese is melted and bubbly, and the dish is heated through.

Step 9: Remove from the oven and let it cool for a few minutes before serving.