Prep the pan and oven: Heat your oven to 350°F (175°C).
Line a 12-cup muffin tin with paper liners.
Whisk dry ingredients: In a medium bowl, whisk 1 1/2 cups flour, 1 1/2 teaspoons baking powder, and 1/2 teaspoon salt. Set aside.
Cream and combine: In a large bowl, beat 1/2 cup softened unsalted butter and 1/4 cup neutral oil with 3/4 cup sugar until light and fluffy, about 2 minutes.
Add eggs and vanilla: Beat in 2 large eggs, one at a time, then 2 teaspoons vanilla. Mix until smooth.
Stir in 1 teaspoon lemon zest if using.
Add dairy: Mix in 1/2 cup sour cream (or Greek yogurt) until combined.
Alternate dry and milk: Add the dry ingredients in two additions, alternating with 1/3 cup milk. Start and finish with dry ingredients. Mix just until no dry streaks remain.
Do not overmix.
Prepare blueberries: Toss 1 cup blueberries with 1 tablespoon flour to coat. This helps prevent sinking.
Fold gently: Fold the berries into the batter with a spatula. Keep the folding light to avoid smashing the berries.
Fill liners: Divide the batter evenly among the liners, about 3/4 full.
If you like extra berries on top, press a few into each portion now.
Bake: Bake for 18–22 minutes, or until the centers spring back and a toothpick comes out clean (a few moist crumbs are fine).
Cool: Let cupcakes cool in the pan for 5 minutes, then move to a wire rack to cool completely.
Optional frosting: For a simple cream cheese frosting, beat 4 ounces cream cheese with 4 tablespoons softened butter, 1 1/2 cups powdered sugar, 1 teaspoon vanilla, and a pinch of salt until fluffy. Spread or pipe onto cooled cupcakes.