Finely chop the onion.
Cut the champignons into thin slices.
Melt the butter in a frying pan and fry the onions and mushrooms for 5 minutes.
In a deep bowl, combine the chicken eggs and cream. Add salt, pepper and whisk.
Pour the egg mixture into the pan and cover with a lid. Cook the omelette over low heat for 5-7 minutes.
When the surface of the omelette hardens, remove it from the heat. The omelette with mushrooms and cream is ready.
Garnish the finished omelette with chopped parsley and cherry tomatoes.