In a large skillet, heat 1 tablespoon of olive oil over medium heat. Once shimmering, add the ground beef and cook, breaking it apart with a spatula, until it’s browned, about 5 minutes. Drain any excess fat, leaving about 1 tablespoon for flavor, then set the skillet aside while you prepare the vegetables.

With the skillet still over medium heat, stir in the finely chopped yellow onion and green bell pepper. Sprinkle with salt and pepper to taste, cooking until softened and lightly caramelized, about 4-5 minutes. Add minced garlic and sauté for another 30 seconds, until fragrant.

Reduce the heat to low and mix in the tomato sauce, unsweetened ketchup, water, pure maple syrup (if using), and apple cider vinegar. Add chili powder and adjust seasoning according to your taste. Stir thoroughly until all components are well integrated and bubbling slightly.

Bring the mixture to a gentle boil, then reduce the heat to low. Cover the skillet and allow it to simmer for about 10 minutes, stirring occasionally.

Before serving, taste and adjust any seasoning, adding more salt, pepper, or chili powder as desired. Spoon over toasted gluten-free buns or baked sweet potatoes.