Make the Meatballs:
Pulse the onion in a food processor until finely chopped. Add it to a large mixing bowl.
Pulse the parsley until finely chopped and add to the mixing bowl along with all of the other meatball ingredients. Mix together until combined.
Form the meatballs and place them on a tray. (make extra and freeze them up to 3 months)
Cook the Meatballs:
Add some oil to a large skillet over medium heat. Add the meatballs to the skillet and cook for 8-10 minutes or until golden all around. Flip them approx. every 2 minutes. Transfer the meatballs to a plate and if the skillet has too much oil, remove it until there are about 3-4 tablespoons left in the pan.
Reduce the heat to low and add the finely chopped onion. Cook until soft and golden. Add the garlic and warm through for a few seconds until fragrant.
Add the spinach and season with a pinch of salt and pepper. Cook until wilted.
Add the cream and broth and cook for 5 minutes. Add the meatballs, crumble the feta cheese on top and warm through for 4-5 minutes.
Remove from the heat and set aside. The sauce will thicken as it sits. Squeeze some fresh lemon juice on top.
Serve with pasta, bread or cauliflower rice. Kali Orexi!