Peel shallot and garlic and chop finely. Heat butter in a saucepan and sauté shallot and garlic. Add thawed peas and ginger. Deglaze saucepan with chicken broth and bring to a boil.
Simmer for about 15 minutes on low heat, add 1 tablespoon of creme fraiche and puree soup. Depending on desired consistency, add extra broth. Season with salt and pepper. Pour soup into bowls, top with dollops of creme fraiche and garnish with mint leaves. Serve.