Preheat your oven to 190°C (375°F). Line a muffin tin with paper liners or grease with butter.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, salt, and lemon zest.
In a separate bowl, mix the vegetable oil, melted butter, eggs, milk, and vanilla extract.
Gradually add the wet ingredients to the dry ingredients. Stir until just combined. Over-mixing can result in tough dry muffins.
Gently fold the blueberries into the batter.
Scoop the batter into the prepared muffin tin. Bake for 20-25 minutes or until a toothpick inserted in the center of a muffin comes out clean.
Remove from the oven and let the muffins cool in the tin for 5 minutes. Transfer to a wire rack to cool completely before serving.
