Preheat to 400 degrees F. Prepare your muffin tin by either greasing the wells or adding paper liners.
Add the flour, baking powder and salt to a large bowl then whisk together and set aside.
Toss the blueberries In about a tablespoon of the dry mixture and set aside. This will help prevent them from sinking in the batter.
In medium bowl, add melted butter, oil, milk, sugar, vanilla, eggs, lemon juice, sour cream, and lemon zest then whisk together until combined.
Pour the wet mixture Into the dry then mix until almost combined. Add the blueberries and fold in.
Transfer batter to your prepared muffin tin filling the wells to the top. Cover with the streusel topping.
Bake for about 20 minutes at 400F. I like to add a ramekin filled halfway with water to keep the muffins nice and moist during the bake but this is optional. Let the muffins cool in the tin for at least 10 minutes before removing.