Preheat the oven to 180 degrees Celsius.
In a small bowl mix the coconut flour, baking powder, sweetener and protein powder.
In a larger bowl mix the egg whites, apple puree and vanilla essence.
Add the dry ingredients to wet ingredients in quarters mixing well each time.
Stir in most of the blueberries (about 3/4).
Line a tin with muffin cases and spoon the batter into each case.
Add the rest of the blueberries on top of each muffin.
Bake for 20-25 minutes until risen and golden in colour. A knife should come out clean.
Cool on a wire tray.
Store in an airtight container.