Melt butter in a 2-quart saucepan until frothing. Remove from heat and stir in flour with a whisk. Cook over low heat for 4 to 5 minutes, stirring constantly. Add 1/2 of the hot milk and whisk until smooth. Add remaining milk and whisk until smooth. Bring to boil, add nutmeg, lower heat and simmer 10 minutes. Can be used hot or cold.
Preheat oven to 400 degrees F.
Bring 4 quarts water to boil. Add 2 tablespoons salt. Blanch the asparagus until just tender (1 minute) and remove to ice bath and refresh. Once the asparagus has cooled, remove from the ice bath and pat dry.
Cut the cooled asparagus in 1/2. Cut the top 1/2 into 1/2-inch pieces and set the pieces aside. Place the bottom halves in a food processor and blend into a fine puree.
In a mixing bowl, mix the pureed asparagus, the bechamel, salt, nutmeg, Parmesan, eggs and yolks. Stir until thoroughly combined. Gently fold in the top halves of the asparagus pieces which had been previously set aside.
Butter an 8-inch bundt pan and coat with bread crumbs. Pour the asparagus mixture into the bundt pan. Fill a 12-inch baking pan 2/3 filled with hot water. Place the bundt pan on the baking pan, so that the bundt is standing in the hot water. Carefully place the baking pan (with the bundt pan) into the oven. Bake until the top of the sformatio is golden brown and a dipped toothpick comes out clean, about 35 to 40 minutes. Remove and allow to cool 15 minutes. Meanwhile, make the fondata.
To make the fondata: Mix the grated fontina, the heavy cream, and the salt and pepper in small saucepan. Heat gently, stirring constantly, until smooth and creamy.
To serve: Turn the sformato out onto a large plate. Cut into 2-inch slices and place the slices on serving plates. Spoon the fondata over the slices and serve immediately.