Preheat oven to 375°F.
For the white sauce, melt butter over medium to medium-high heat in a saucepot. Whisk in flour, cook 1-2 minutes then whisk in milk and season with salt, pepper and a little nutmeg. Let thicken to coat a spoon and adjust seasoning. Temper the egg yolks with a ladle of sauce then add them into to the pot. Stir in cheese and remove from heat.
Meanwhile, for the green layer, heat EVOO in a large skillet. Brown and crumble sausage then add chilies and garlic. Cook to soften; deglaze pan with wine or stock and add in rabe and spinach. Combine and season with salt and pepper to taste.
Combine ricotta with egg yolks, grated cheese and parsley.
Soak lasagna noodles 4-5 minutes in warm water. Drain and separate.