Pat chicken dry w/paper towel, then sprinkle w/s&p. Dredge chicken pieces completely in flour, then shake off excess & brown in 4T melted butter in large skillet over med-high heat. Once cooked (3-4min), transfer chicken to plate.
Melt additional 2T butter & sauté onions with rosemary until lightly browned. Add mushrooms & sauté until most liquid has evaporated.
Push veggies to side, then add Garlic & Chili Pepper Pastes & caramelize for 1 minute. Add wine & deglaze, scraping up brown bits from bottom of pot. Add Artichokes, Sun-Dried Tomatoes, heavy cream, pinch s&p & reserved chicken. Simmer 2-3 min or until sauce has reduced & begun to thicken from flour.
Meanwhile, cook pasta in salted boiling water for 2min less than suggested time. Transfer pasta + 1c pasta water to skillet & mix. Allow pasta to finish cooking in sauce.
Turn heat off, then fold in spinach & remaining butter.