Then add the sliced potato and continue to cook for a few min. Add the chicken broth, bring to a simmer and cover. Cook for about 15 min, until the potatoes and fennel are soft.
Then add the peas and cook for only a few min, to help keep their green. Mix the soup and season with salt and pepper to taste. Check the consistency and add more broth if necessary.
Strain the soup in a chinois to have a smooth consistency. Whip the cold cream (not too firm) with 1 teaspoon horseradish, salt and pepper. Take glasses and pour some soup in each. Top with cream and chopped mint. Serve immediately