Preheat oven to 200°C/180°C. Lightly grease a 12-hole muffin pan

Sift flour and soda together in a large bowl. Stir in spinach, onion and half of the feta. Combine remaining ingredients in a bowl, whisking well to combine

Fold through dry mixture until just combined. Spoon into prepared cases and sprinkle with remaining feta. Bake for 25-30 minutes until cooked when tested with a skewer