These muffins freeze wonderfully, so feel free to make a double batch and chuck the extras in the freezer for a rainy day.
Preheat your oven to 200°C/400℉. Grease or line a muffin tray with muffin tin liners.
Add all the ingredients into a blender (except the fresh blueberries), and blitz until just barely mixed together, but before the contents reach a smooth puree consistency.
In a separate bowl, gently toss the fresh blueberries with 1 Tablespoon of gluten-free flour until lightly coated. This will help prevent the blueberries from sinking into the muffins. Add the coated blueberries to the wet mixture and stir them in by hand.
Using a tablespoon, scoop the batter into the lined muffin tray.
Bake the blueberry muffins for 15-25 minutes at 400F (200C).
Serve with extra blueberries, lemon zest, and confectioner's sugar, if desired. Enjoy warm, or store in an airtight container for up to 3 days.