Cut potatoes into cubes, soak in water for 5 minutes, and drain. Microwave in a heatproof container covered with plastic wrap for 6 minutes at 600W.

Mash the warm potatoes, add butter, milk, salt, and pepper, and mash until smooth to make mashed potatoes.

Finely chop the carrot and onion.

Heat salad oil in a frying pan, add carrot and onion, and sauté over medium heat until onion becomes translucent.

Add ground meat, break it apart while cooking, then add ketchup, medium-thick sauce, and salt and pepper. Stir to combine and make meat sauce.