Preheat oven to 400°F and line a baking sheet with parchment paper.
Combine the beef, egg, feta, panko, onion, garlic, 1 teaspoon oregano, cumin, 1 teaspoon salt, and pepper.
Shape into 18 meatballs and place on the baking sheet.
Bake for 15–20 minutes, or until cooked through.
Melt the butter in a large skillet. Remove from the heat and toss with the zucchini noodles, lemon zest, lemon juice, remaining oregano, and remaining salt.
If using frozen zucchini noodles, cook and drain them before tossing with the butter mixture.
Serve the meatballs over the lemon butter zucchini noodles.
