6 tbsp. unsalted butter
1 lg. yellow onion, chopped
2 qts. chicken stock
2 c. dry white wine
2 lg. potatoes, peeled and diced
1 1/2 c. milk
2 c. heavy cream
4 oz. shredded Mozzarella
4 oz. shredded Fontina
4 oz. crumbled Gorgonzola
4 oz. grated Parmesan
2 lg. egg yolks
1/2 tsp. nutmeg
Salt and pepper

Melt butter, add onion and cook about 10 minutes until soft. Add chicken stock, wine, and potatoes and simmer 25 minutes. Stir in milk and 1 1/2 cups cream. Puree soup in blender and return to pot. Heat over medium low heat. Add all the cheese and stir until cheese melts. Whisk egg yolks and 1/2 cup cream in bowl. Whisk 1/2 c. hot soup into cream then add to hot soup. Stir in nutmeg and season to taste. Do not let soup boil or it will separate. Serve with croutons.