Preheat the oven to 170°C. Grease and line a medium cake pan or 4 mini cake pans. You can use silicon moulds - these don’t need to be greased.
In a mixing bowl whisk together the flour, oats and baking powder.
In another bowl, whisk together the oat milk and lemon juice. Set aside for 5 minutes to curdle.
Add the sugar, eggs, lemon zest, vanilla extract and oil.
Add the wet ingredients to the dry ingredients and mix until well combined.
Coat the blueberries with the remaining flour, then gently fold them into the batter.
Tip the batter into the prepared pan(s) and bake for 20-30 minutes or until an inserted toothpick in the center of the cake comes out clean.
Decorate, frost or glaze the cake(s) to your liking.