Preheat the oven to 220°C/40F or 200°C fan and line a 12 cup muffin tin with cupcake liners.
Grate the cheese, and crumble the feta. Melt the butter. Set aside.
150 grams feta, 120 grams mild Edam, 75 grams melted butter
Cook the spinach until just welted. This can be done on the stovetop, or place the spinach in a colander and pour about 750mL of boiling water over the spinach. Once the spinach has cooled, squeeze most of the liquid out, and dice the spinach.
120 grams baby spinach
In a large mixing bowl, whisk together the flour, herbs, cornstarch and baking powder.
300 grams plain flour, 50 grams cornstarch, 3 teaspoons baking powder, 3 teaspoons dried mixed herbs
Add in the feta, spinach and half the cheese (the other half will be sprinkled on the top of the muffins). Toss with the flour to coat and break up any large pieces or clumps of spinach.
150 grams feta, 120 grams mild Edam
Whisk together the eggs, milk, yoghurt and melted butter.
2 eggs, 140 grams Greek yogurt, 250 grams milk
Pour the wet ingredients over the dry ingredients and mix until just combined.
Divide the muffin batter between the cupcake liners and top with the remaining cheese.
Bake the feta and spinach muffins at 220°C/340F or 200°C fans for 5 minutes. Turn down the oven to 200°C/390F or 180°C fans and bake for a further 12 to 15 minutes or until just baked.
Let the muffins cool in the tin for 5 minutes before turning them onto a wire cooling rack.