- In a bowl, combine all the ingredients. Season with salt and pepper. Shape into 8 meatballs, using about 1/3 cup (75 ml) of the mixture for each. Set aside.
- In a large non-stick skillet over medium heat, soften the onion and garlic in the oil. Add the tomatoes and bring to a boil. Season with salt and pepper. Let simmer for 5 minutes. Add the meatballs and cover. Let simmer for 10 minutes, turning the meatballs halfway through cooking. Adjust the seasoning.
- In a large skillet over high heat, sauté the spinach in the oil until wilted. Season with salt and pepper. Drain in a sieve. Set aside.
- On a grill pan or in a hot oven, toast the buns. Divide the wilted spinach on the bottom buns and add the meatballs. Drizzle with the tomato sauce. Cover with the top buns.