Heat the oven to 375 degrees F. Spray a 9in springform pan with cooking spray and dust lightly with a handful of grated parmesan cheese and set aside
In a medium saucepan, melt the butter over medium heat, once bubbling add in the flour and whisk continuously for 2-3 minutes until smooth. Add in the white wine followed by the milk, and cook for until thick, about 15 minutes. Season with salt, pepper, nutmeg and cayenne. Remove from heat and stir in the egg, fontina and 1 cup parmesan. Place over super low heat to keep warm.
Meanwhile, bring a large pot of salted water to boil and cook pasta according to package directions until al dente. Drain and set aside.
In a medium saucepan over medium high heat, add olive oil and crumble in the sausage cooking until browned 5-6 minutes, remove sausage to a bowl and toss in the spinach stirring just to wilt, about 2-3 minutes. Remove from heat. Combine with the cooked sausage and crushed red pepper and set aside.
Stir ricotta and pesto together, set aside.
Combine the cooked pasta and the cheese sauce, layer 1/3 of it into the prepared pan followed by 1/3 of the ricotta mixture and 1/3 of the spinach and sausage mixture. Repeat so you have three layers ending with sausage and spinach. Sprinkle with the remaining 1/2 cup parmesan cheese on top.
Bake in the oven till golden brown 35-40 min. Remove and let sit for about 30 mins. Remove the side from the springform pan sprinkle with torn basil and more parmesan.