Heat the butter and olive oil in a large saucepan.
Add the garlic, red pepper flakes, rosemary, salt, and pepper and sauté for 1 minute.
Add the chicken stock, half-and-half, and milk and bring to a boil.
Remove from the heat and slowly sprinkle the cornmeal into the hot milk while stirring constantly with a whisk.
Cook over low heat, stirring constantly, for a few minutes, until thickened and bubbly.
Off the heat, stir in the Parmesan.
Pour into a 9 X 13 X 2-inch pan, smooth the top, and refrigerate until firm and cold.
Cut the chilled polenta into 12 squares, as you would with brownies.
Lift each one out with a spatula and cut diagonally into triangles.
Dust each triangle lightly in flour.
Heat 1 tablespoon olive oil and 1 tablespoon butter in a large sauté pan and cook the triangles in batches over medium heat for 3 to 5 minutes, turning once, until browned on the outside and heated inside.