Cook the barley groats in salted water according to the instructions on the packet and remove them from the bag.
In the meantime, peel the carrots and onions, cut into cubes and sauté in the butter for 10 minutes. Separate the eggs and beat the egg whites until stiff. Mix the egg yolks with the cream and season with salt and pepper.
Mix the egg mixture with the vegetables and the barley groats and fold in the egg white. Put everything in a greased casserole dish, sprinkle with the cheese and bake in a non-preheated oven at 160 ° C for about 25 minutes (if necessary, turn up the temperature towards the end so that the casserole gets a little brown).