Mix in a measuring jug the oil, egg and milk and vanilla essence
In a separate bowl add dry ingredients and mix with a fork, don’t use an electric mixer
Then add wet ingredients to dry and just incorporate slowly till dry ingredients are wet and lastly add the blueberries and just stir through slowly so you see it’s all over in your mixture.
Spray a muffin sheet or use paper liners I didn’t I just spayed my tin, add spoonfuls into muffin tins, it makes 10 big muffins do in the two empty muffins holes I put two tablespoons of water in each empty hole.
I also took a bit extra sugar and sprinkled each muffin on the top with a little sugar.
Bake at 180ºC  till golden or cooked, normally 15 to 20 minutes depending on your oven.