In a skillet over medium heat, sautee garlic in 2T of ghee add spinach and reduce heat to low. Season with sea salt and crushed red pepper, cook just until soft and wilted. Remove from pan and set aside, will yield approx 1 cup cooked spinach.
Melt remaining 2T of ghee in the same (dirty) skillet the spinach was cooked in - to be added to the mixture in the next step.
Combine all other ingredients (except feta cheese) and mix until smooth.
Add feta and spinach to batter and gently fold in, preferable by hand. You can make the batter in your food processor or blender then pulse to combine spinach & feta, but you do not want to finely chop the spinach, it should stay in large pieces.
Preheat waffle iron and cook waffles according to factory instructions. You want your waffles to be lightly brown and crispy - the crispier the better!
Transfer cooked waffles to a cooling rack and allow to cool slightly before serving.