Wash the spinach if needed, then chop it very finely. Place in a clean kitchen towel and twist over the sink to squeeze out as much water as possible. You want it almost crumbly-dry - excess moisture makes soggy meatballs. This step matters more than you think.

In a large bowl, combine the ground chicken, squeezed-dry spinach, Parmesan, almond flour, garlic, egg, Italian seasoning, red pepper flakes if using, salt, and pepper. Use your hands to mix gently until just combined - overworking makes tough meatballs.

Wet your hands with cold water (prevents sticking) and roll the mixture into 20 meatballs, about 1.5 inches across. Place on a large rimmed baking sheet lined with parchment or lightly oiled. They can be close but not touching.

Drizzle the olive oil over the meatballs and roll them gently to coat. Bake at 425 degrees F for 20-25 minutes, until deeply golden on top and cooked through to 165 degrees F internal. The bottoms should have some nice brown bits.

Let the meatballs rest for 5 minutes - they firm up and hold together better. Serve with extra grated Parmesan, over zucchini noodles, with a simple tomato sauce, or alongside a crisp salad.