Prepare the remaining ingredients specified in the recipe. Remove the eggs from the refrigerator. Wash the champignons and dry with a paper towel.
Cut the mushrooms into slices.
Separate the whites from the yolks. Place the whites in one bowl and the yolks in another. Beat the whites with a mixer into a strong foam. Add milk, salt and pepper to taste to the yolks and shake well with a fork.
Heat a frying pan with butter and a drop of vegetable oil. Fry the mushrooms for 10 minutes over low heat and remove from the pan.
Pour the yolk mixture into the mushroom pan so that it is evenly distributed over the bottom of the pan.
Wait 2 minutes for the whites to cook, then place the previously fried mushrooms on top of the whites.
The omelette is ready. Bon appetit!
Sprinkle the finished omelette with finely chopped green onions and garnish with cherry halves.