Preheat oven to 350°F (175°C). Grease and flour a 9-inch round cake pan or bundt pan.
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
In a large mixing bowl, beat butter, oil, and sugar until light and fluffy.
Add eggs one at a time, mixing well after each. Stir in sour cream, lemon zest, lemon juice, and vanilla.
Gradually fold in the dry ingredients until just combined. Do not overmix.
Gently fold in the blueberries (coated in flour to prevent sinking).
Pour batter into prepared pan and smooth the top.
Bake for 40–45 minutes, or until a toothpick inserted into the center comes out clean.
Allow cake to cool in the pan for 15 minutes, then transfer to a wire rack.
(Optional) Whisk together powdered sugar and lemon juice, then drizzle over cooled cake.