Preheat oven to 350°F. In a food processor add the walnuts, garlic, salt, red pepper flakes and process until like cornmeal in texture. Add the basil leaves and purée. With motor running add the olive oil for a thick paste. Set aside.
For the meatballs in a medium size bowl add the ground turkey with the pesto, egg, breadcrumbs. Mix together by hand until incorporated completely. Add more breadcrumbs if the mixture is too wet. Use a 2-inch scoop or roll into small balls, about the size of a golf ball, making 16. Spray a baking dish with oil and add the meatballs. Set aside.
In a large frying pan add the butter over medium heat. Stir in the flour using a whisk and cook until light golden in color. Gradually add the milk a little at a time, stirring often to incorporate completely. Add the pinch of nutmeg and Parmesan cheese, whisking until you have a smooth sauce.
Pour the Mornay sauce over the meatballs in a 9”x9” greased pan. Cover with foil and bake for 25 minutes. Remove foil and lightly brown the top for another 5 minutes.
Pan fry the prosciutto with olive oil and drain on paper towel when crisp. Chop the basil and set both aside. Crumble crispy prosciutto and julienned basil on top of baked meatballs and serve alongside steamed vegetables.