2) Preheat the oven to 120°C.
3) Cut the polenta into 5 by 2.5-cm pieces. Heat the oil in a heavy large skillet over medium-high heat.
4) Working in batches, fry the polenta pieces until golden brown on all sides, about 3 minutes per side. Using tongs, transfer the polenta pieces to paper towels and drain. Place the polenta pieces on a baking sheet and keep warm in the oven while cooking the remaining batches.
5) Transfer the polenta pieces to a serving platter. Sprinkle the polenta with the Parmesan cheese and salt. Serve, passing the marinara sauce alongside.