Heat the olive oil in a large skillet over high heat. Sauté the garlic in the olive oil until fragrant, just 10-15 seconds. Add the spinach leaves and sliced roasted red pepper and toss to coat in olive oil. Pour in the white wine and stir in the olives. Simmer over medium-high heat and cook until the liquid is reduced by half. Remove from heat, season with salt and pepper, and drizzle in the balsamic vinegar.
Bring a large pot of water to a boil. Cook the campanelli according to package directions. Drain well, and add to the skillet. Fold the pasta in to completely coat in the sauce. Serve hot, topped with the crumbled feta.