Wash the spinach well to remove any dirt / sand and dry them well. Trim off the stems and chop them finely.
Preheat the oven to 200 C | 400 F. Line a 12-cup muffin pan with paper liners or grease and flour the pan.
In a large bowl, sift flour, baking powder, baking soda, cayenne pepper, pepper powder. Add spinach, sun-dried tomatoes, feta, 2 tbsp parmesan and stir to combine.
In another bowl, add milk, yogurt, melted butter and whisk until well combined. Add this to the flour mixture and mix with a spatula until just combined.
Fill each muffin cup about ¾th full. Sprinkle the remaining parmesan over the muffins.
Bake for 20-22 minutes or until a toothpick inserted in the center comes out clean. Place the muffin pan on a rack and allow to cool.