Peel and cut the red onion in small pieces.
Mix the minced meat, red onion, salt, and pepper in a bowl. Divide in 4.
Form a bowl and press together in your hands. Place the burgers in a hamburger press and place on the side for later.
Time to make the sauce. In a saucepan melt the butter.
Add the milk and the chanterelles and continue stirring until thickens.
Melt some butter in a frying pan and fry the burgers on each side, make sure it´s slightly pink in the middle.
Place salad leaves on the burger bottom, continue with the burger, cheese sauce and avocado.