1Prepare polenta: bring water to a boil, add salt, and pour cornmeal in a thin stream, whisking continuously. Cook for 5 minutes until thickened, stirring constantly. Add Parmesan and butter, mix well, then spread on a baking sheet lined with parchment paper and let cool and set.
2Once polenta has set, cut into sticks (like french fries). Drizzle with olive oil and season with salt and pepper.
3Place polenta sticks in the air fryer basket in a single layer. Cook at 200°C (400°F) for 12-15 minutes, shaking the basket halfway, until golden and crispy.
4While polenta cooks, prepare saltimbocca: place each chicken breast between two sheets of plastic wrap and pound to an even thickness of about 1 cm (1/2 inch). Season with salt and pepper.
5Place 2 sage leaves on each chicken breast, then wrap with 2 slices of prosciutto. Secure with toothpicks if needed.
6Heat butter in a skillet over medium-high heat. Add chicken saltimbocca and cook for 3-4 minutes per side, until golden and cooked through.
7Remove chicken from skillet and keep warm. Pour white wine into the skillet, scraping up any browned bits. Let the sauce reduce by half, about 2 minutes.
8Serve chicken saltimbocca drizzled with the pan sauce, alongside crispy polenta sticks.