Step 1: Preheat your oven to 350°F (175°C) for even baking.
Step 2: Grease your muffin tin with coconut oil or butter, or use paper liners.
Step 3: In a large bowl, whisk together the flour, baking powder, baking soda, paprika, sea salt, and black pepper.
Step 4: In another bowl, mix the milk, melted coconut oil (or butter), beaten egg, and lemon zest.
Step 5: Pour the wet mixture into the dry ingredients and stir gently.
Step 6: Fold in the spinach, feta, and chives gently with a spatula.
Step 7: Fill each muffin cup about ¾ full with batter.
Step 8: Bake for 18-20 minutes, or until a toothpick comes out clean.
Step 9: Cool in the tin for a few minutes, then transfer to a wire rack.