Preheat the oven to 400 degrees F. Line a baking sheet with foil and add the polenta in a single layer; brush both sides with 1 tablespoon olive oil and season with salt and pepper. Bake until golden, about 20 minutes.
Meanwhile, season the pork chops on both sides with the rosemary, 1/2 teaspoon salt and a few grinds of pepper. Heat 1 tablespoon olive oil in a large skillet over medium-high heat. Working in batches if needed, add the pork chops and cook until golden, about 2 minutes per side. Transfer to a separate baking sheet.
Add the remaining 1 tablespoon olive oil to the skillet. Add the garlic and cook until just golden, 1 minute. Add the spinach and season with salt and pepper. Cook, stirring, until just wilted, 1 to 2 minutes. Top the pork chops with the spinach and 1 cheese slice each; bake until the cheese melts, about 5 minutes.
Meanwhile, add the broth to the skillet. Cook over medium-high heat until reduced by half, about 4 minutes. Add the butter and stir until melted. Top the pork with the pan sauce and peppers; serve with the polenta.