Preheat oven to 325°F. Mix together the rub ingredients in a small bowl, then liberally season the beef with the rub, setting aside 1 tablespoon for cooking. Heat oil over medium-high in a Dutch oven and sear the beef until brown on all sides. Remove beef, add garlic and onion to the pot and sauté for 2 minutes. Add tomatoes with pulp, stock, 1 tablespoon rub and stir. Return beef to the pot, cover with lid or foil and bake until fork tender, approximately 2 hours. When the beef is tender, remove from oven and remove the beef from the pot. Place pot over medium-high heat and reduce liquid by half. Once cooled, shred the beef into bite-sized pieces and return it to the pot.

Meanwhile, in a separate heavy-bottomed pot, heat milk, water and salt, granulated garlic and paprika over high heat. Just before mixture begins to boil, slowly pour in the cornmeal while whisking. Turn heat to low and continue to cook, stirring frequently, until nicely thickened, approximately 30–40 minutes. Add mascarpone and fontina; stir until melted.

Raise oven heat to 425°F. Spread the polenta in a shallow baking dish and add the braised beef atop the polenta. Sprinkle the cheeses evenly over the top and bake until golden brown and bubbly, approximately 10 minutes. Remove from oven and cool 10 minutes. Serve with fresh basil and a drizzle of good olive oil.