Peel carrots. Peel and wash the potatoes. Cut both into pieces. Peel onion and chop finely. Melt butter in a pot. Steam onion, carrots and potatoes for about 2 minutes until colourless. Deglaze with broth. Simmer for 10-15 minutes, stirring occasionally.
In the meantime, cut the toast into cubes. Heat oil in a pan. Fry the diced toast for 2-3 minutes while turning it over. Take out and drain on kitchen paper. Fry the bacon in the pan until crispy. Wash the chervil, shake dry and chop coarsely except for a few leaves
Stir 50 g crème fraîche into the soup. Season to taste with salt, pepper and nutmeg. Puree finely with a chopping stick. Arrange the soup in bowls. Break the bacon into pieces. Add 1 tsp. crème fraîche to each soup and garnish with croutons, bacon and chervil