2 tbsp. olive oil
 5 cloves garlic, minced
 1 medium yellow onion, finely chopped
 8 oz. ground beef
 1 (10-oz.) package frozen chopped spinach, thawed and squeezed dry in paper towels
 8 eggs, lightly beaten
 1⁄4 cup finely grated Parmesan
 Crusty Italian bread, for serving
 Kosher salt and freshly ground black pepper, to taste