Preheat oven to 350 degrees.

In a small skillet, warm olive oil over low heat. Add onion and sauté until soft but not browned. Add garlic and sauté for 30 seconds more. Add spinach and sauté for about 5 minutes. Remove from heat.

In a large bowl, mix the ground beef, eggs, bread crumbs, Parmesan cheese, salt, and pepper. Add the cooked spinach, mixing thoroughly.

In a 9x13 inch baking pan (glass is preferred), shape the meatloaf into a rectangle. Bake for about an hour, taking care not to overcook or the meat will dry out. The meatloaf can be a little pink in the middle.