Place a cast iron skillet over medium-high heat and melt the butter. Once the pan is nice and hot, add the beef mince and break it up with a wooden spoon and let it brown, without stirring, for about 5 minutes or until the bottom side has a nice brown colour. Note - I add the salt and pepper at this stage, topping first one side, then the other once I "flip" the mince.
Use the spoon and turn the mince over to brown the other side for another few minutes, then remove the mince onto a plate and set aside.
In the same skillet, add the onion, garlic, pepper, courgette, mushrooms and spices and cook, stirring frequently and adding more butter or oil if necessary, for another 5-8 minutes before adding back the beef and the can of tomatoes.
Let simmer for 10 minutes, stirring occasionally, then add your cheese and either cover or place under the grill until the cheese is melted and delicious!
Serve hot!
Recipe by Sprinkle of Green at https://www.sprinkleofgreen.com/cheesy-homemade-beef-taco-skillet