Remove polenta from casing, cut into ten 1/2-inch slices (cakes), and pat dry with paper towels.
Brush both sides of polenta cakes with oil, and set aside.
Heat a grill pan over high heat until hot. Lay polenta cakes in one layer on the pan; grill for 8-10 minutes on each side or until both sides are golden and crunchy and have grill marks.
Remove cakes from the grill pan and let cool on a wire rack. Preheat the oven to 350°.
Coat a baking sheet with cooking spray. Arrange the grilled polenta cakes on the baking sheet. Place 1 tablespoon of tomato sauce on each slice, then add 1-2 teaspoons Parmesan to each. Bake for 15 minutes.
Garnish with basil, salt, and pepper. Serve warm.