Set your oven to 350 (180C) and spray or grease a 12-count muffin pan.
Get yourself 2 mixing bowls, sift the whole-wheat flour, baking powder, brown sugar and wholegrain oats into one of them. In the other crack in and lightly beat the two eggs, then stir in the yogurt and vegetable oil.
Add the bowl of wet ingredients to the dry, add the frozen blueberries and stir until just combined, take care not to over mix and don’t be too worried if there are a couple of traces of flour. During the baking process the mixture will continue to blend and any lumps will be gone.
Spoon the mixture evenly into the prepared muffin pan and bake for around 25 minutes until they are nice and golden on top and a wooden skewer comes out clean. Cool them in the pan for 5 minutes before turning out.