Combine buttermilk, hot sauce and garlic in a medium nonreactive bowl. Add chicken thighs. Cover and marinate for at least 4 hours or overnight.
Combine flour, garlic powder, salt and pepper in a shallow dish. Add eggs to another shallow dish and breadcrumbs to a third shallow dish.
Working one at a time, remove the chicken thighs from the marinade. Coat with the flour mixture, then the egg. Finally, coat both sides with breadcrumbs. Coat both sides of the chicken with cooking spray.
Lightly coat the basket of the air fryer with cooking spray. Place the chicken thighs in a single layer in the basket. (Depending on the size of your air fryer, you may have to cook in batches.)
Cook the chicken at 400°F until an instant-read thermometer inserted in the center of the chicken registers 165°F, turning the thighs over halfway through, about 16 minutes. (If cooking in batches, cooking time for the second batch may be shorter.)
Cook the pasta in a pan of boiling salted water according to the packet instructions, then drain, reserving a mugful of cooking water. Meanwhile, peel and finely slice the garlic. Place it in a large non-stick frying pan on a medium-high heat with ½ a tablespoon of olive oil, followed 1 minute later by the mushrooms, tearing up any larger ones. Season with sea salt and black pepper, and cook for 8 minutes, or until golden, tossing regularly.
Toss the drained pasta into the mushroom pan with a splash of reserved cooking water. Finely grate in most of the Parmesan, stir in the crème fraîche, taste, season to perfection, and dish up, finishing with a final grating of Parmesan.
Bring a large pot of lightly salted water to a boil. Add ziti pasta, and cook until al dente, about 8 minutes; drain.
In a large skillet, brown onion and ground beef over medium heat. Add spaghetti sauce, and simmer 15 minutes.
Preheat the oven to 350 degrees F (175 degrees C). Butter a 9×13 inch baking dish. Layer as follows: 1/2 of the ziti, Provolone cheese, sour cream, 1/2 sauce mixture, remaining ziti, mozzarella cheese and remaining sauce mixture. Top with grated Parmesan cheese.
Bake for 30 minutes in the preheated oven, or until cheeses are melted.