Peel the onion and the garlic and mince them. Heat the oil and fry the onion and the garlic until glazed. Add the minced meat and stir it until it has lightly browned. Add the mushrooms that have been cleaned and sliced. Clean the pepper, cut it in thin strips and add to the mixture in the pan. Season to taste with taco seasoning, tomato ketchup, pepper and salt and simmer it all for another 3 minutes.
Heat the tacos according to the directions on the package and fill them with the mixture of mushrooms and minced meat . Garnish with finely cut chives. Serve the tacos on a bed of thinly sliced iceberg lettuce.
Tip: sprinkle grated cheese over the filling. Or serve pureed avocado with some salt, pepper and lemon juice with the iceberg lettuce. You can puree it in a blender or food processor.