In a medium-sized bowl, add in flour, oats, bread soda, baking powder, cornflour and salt. Mix together and set aside.
In a small bowl, add sugar and lemon zest. Using your fingers, combine them to release all of the lemon oils and fragrances. Do this for 2 minutes and set aside.
Into the same bowl, add oil, eggs, vanilla, and buttermilk. Whisk until well combined.
Add in dry ingredients. Pour the dry ingredients into the wet and using a spatula, gently fold to create a soft muffin batter.
Gently toss the blueberries in 1-2 tsps of flour before adding them into the mixing bowl. Then add into the bowl and mix in a few times.
Evenly divide the batter between your liners.
Bake the muffins at 375°F for 20-25 minutes.
These muffins stay fresh covered at room temperature for a few days