Heat the oven to 190 C (gas mark 5), and grease some muffin cups*. Stir (no electric mixers here!) the following together until just combined, but still a bit lumpy (the secret to good muffins):
1.5 cups GF flour blend (I use Doves Farm)
1 egg (like all my ingredients, I use organic)
1/3 cup sugar
1/3 cup sunflower oil
1/3 cup coconut milk (I use full-fat organic)
1/3 cup water
1 tbsp cider vinegar
2 tsp baking powder
I'm quite particular about how I do the blueberries -- I don't just stir them in, hit or miss. Oh no. I put half the batter into the bottom of each cup, then add a pile of blueberries, then top with batter, then use a small spoon and give each muffin a quick fold, to mix the berries but not crush them. Finally, I add two or three berries to the top of each muffin, and bake.
This makes about 6 regular size, or using the jumbo cups pictured, 4 muffins. It can easily be doubled for a bigger batch, and they freeze well.