Salt and pepper both sides of each chicken thigh. Warm olive oil in a large cast iron skillet over medium-high heat until hot and shimmering. Place chicken thighs in a single layer and sear undisturbed for four minutes to develop flavor and color. Flip each piece and sear for another two minutes. Transfer chicken pieces to slow cooker insert coated with nonstick spray.
Add sliced onions to the skillet, on top of the oil and chicken drippings. Sprinkle with turmeric, herbs de Provence, and extra salt and white pepper to taste, and sauté until onions have softened, about three or four minutes. Add minced garlic and sauté until fragrant, about 30 seconds more.
Pour white wine over the vegetables and deglaze the skillet. Simmer until the wine has mostly evaporated. Transfer to the slow cooker insert atop the chicken.
Open the cans of whole tomatoes and pulse them, with their juice, a few times in your blender. Pour into slow cooker insert. Top with bell peppers, sliced mushrooms. Give the top layers a good stir, trying to keep the chicken on the bottom as much as possible.
Cover slow cooker with a lid, set to cook on HIGH for four hours. After four hours, transfer chicken to a plate and move to a 200°F oven to keep warm.
Stir baby spinach into remaining sauce and vegetables and set to cook on HIGH for another hour, this time uncovered.
While the sauce reduces, cook the pasta. Bring a pot of salted water to a boil and cook the egg noodles according to package instructions until al dente. Drain, and drizzle with extra virgin olive oil if desired.
Prepare a large serving platter with all the pasta, followed by the chicken thighs, then vegetables, then a generous spoonful of sauce, and sprinkle with chopped parsley and grated Parmesan. Alternately, you can assemble individual bowls with portions of the ingredients in the same order.
Serve to enthusiastic applause.
