Step 1: Prepare the Spinach

1. If Using Fresh Spinach: Place the fresh spinach in a steamer basket or saucepan with a splash of water. Steam over medium heat until wilted, about 3-4 minutes. Transfer the spinach to a clean kitchen towel and squeeze out any excess water. Chop the spinach finely.
2. If Using Frozen Spinach: Thaw the spinach completely, then place it in a fine-mesh strainer or clean kitchen towel and squeeze out as much water as possible. Properly draining the spinach is key to ensuring the spinach balls hold together.
3. Set Aside: Place the prepared spinach in a large mixing bowl and set aside.

Step 2: Prepare the Spinach Mixture

1. Combine Ingredients: To the bowl with the spinach, add the breadcrumbs, grated Parmesan, shredded mozzarella, chopped onion, minced garlic, parsley, salt, black pepper, and nutmeg (if using). Stir to combine all ingredients evenly.
2. Add the Eggs: Crack the eggs into the bowl and mix well until the mixture starts to come together and holds its shape. The eggs help bind the ingredients, creating a cohesive mixture that’s easy to shape into balls.
3. Adjust the Texture: If the mixture seems too dry, add a splash of water or an extra egg. If it’s too wet, add a few more breadcrumbs to help absorb the excess moisture.

Step 3: Shape the Spinach Balls

1. Preheat the Oven: Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper or a silicone baking mat.
2. Form the Balls: Using your hands, scoop about 1 tablespoon of the mixture and roll it into a ball. Repeat with the remaining mixture, placing each spinach ball on the prepared baking sheet. You should have about 24 spinach balls.
3. Brush with Olive Oil: Lightly brush each spinach ball with a small amount of olive oil. This helps them achieve a golden, crispy exterior while baking.

Step 4: Bake the Spinach Balls

1. Bake: Place the baking sheet in the preheated oven and bake for 18-20 minutes, or until the spinach balls are firm and lightly golden on the outside. Turn them halfway through baking for even browning.
2. Cool Slightly: Remove the spinach balls from the oven and let them cool for a few minutes before serving. They’ll firm up as they cool, making them easier to handle.

Step 5: Serve and Enjoy

1. Arrange on a Serving Platter: Transfer the spinach balls to a serving platter. Garnish with extra chopped parsley if desired.
2. Serve with Dipping Sauces: Serve the spinach balls with a selection of dipping sauces like marinara, ranch, honey mustard, or tzatziki. The dipping sauces add flavor and make them even more enjoyable.