Heat oil over medium-low heat. Stir in onion and cook and stir until it turns translucent. Add garlic and cook stirring for a minute. Add minced meat and cook and stir, breaking into small clumps until it browns.
Pour in tomato sauce, add bell pepper, salt, and pepper. Stir and cover. Simmer for 3 minutes.
Uncover and mix in the optional ingredient of your choice, or none at all if you so prefer. Taste and season with salt and pepper to taste if needed. Remove from the heat.