Preheat the oven to 220C/Gas 7.
1) Place water on to boil for pasta. When it comes to the boil, salt the water and cook pasta until al dente. Drain.
2) Whilst pasta is cooking, place veal in a mixing bowl and add to it the egg, garlic, sage, bread crumbs, cheese, nutmeg and salt and pepper, to taste. Drizzle a little extra-virgin olive oil into the bowl, mix and roll small 2.5cm balls. Arrange balls in a single layer on a nonstick baking sheet and bake 8 to 10 minutes in a hot oven until meat is golden and firm.
3) Toast the walnuts and place them into a food processor. Grind the walnuts and reserve.
4) In a deep skillet over medium heat melt butter. Whisk flour into butter and cook a minute then whisk in wine and reduce by half. Whisk in stock, when it bubbles and begins to reduce, stir in the cream and reduce heat to medium low. Simmer to thicken the sauce a bit, 2 to 3 minutes, melt in the gorgonzola and stir in the ground walnuts then season the sauce with pepper, to taste, and maybe a pinch of salt.
5) Shred the greens into thin strips.
6) Toss the pasta with the sauce. Serve pasta garnished and topped with a generous mound of greens to mix in as you are eating.