Firstly, I used button mushroom and processed cheese. You can pick any.

Heat butter in a pan. Add cleaned and sliced mushroom to it. Let it release water.

When it shrinks, add milk and let boil.

Cut cheese in small pieces or simply grate and add to the mushroom. Let boil a little. The milk will thicken. Cook to your desired consistency.

Just before switching off the heat, add salt and pepper. Be careful with the salt since the cheese may add a little saltiness.

Place the prepared mushrooms on toast. Enjoy!