I found a version of this recipe on Taste's Website and adapted it to be gluten free.
My local Muffin Break sells these muffins at around $4.50 a pop and my kids love them, so I decided to find a similar recipe and start making them myself.
Oil, to grease
2 cups gluten free self-raising flour
250g frozen spinach (squeeze the excess water out)
150g feta cheese, crumbled
1/2 cup chopped semi-dried tomatoes
2 tbs finely grated parmesan
1 1/3 cups milk
90g butter, melted
Preheat oven to 200°C. Brush twelve 80ml (1/3-cup) muffin pans with oil to lightly grease.
Sift flour into a bowl. Add spinach, feta, tomatoes and parmesan, and stir to combine. Use a fork to whisk together milk, butter, egg until well combined. Add milk mixture to flour mixture and use a metal spoon to stir until just combined (do not over mix).
Spoon mixture into prepared pans. Bake for 20 minutes or until a skewer inserted into the centre comes out clean. Turn out onto wire rack to cool. Serve warm or at room temperature.