Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.

In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt.

In another bowl, mix the full-fat sour cream, whole milk, and a portion of fresh lemon juice until smooth.

Gently toss blueberries in the remaining lemon juice and a touch of flour.

In a large bowl, beat the unsalted butter and granulated sugar until light and fluffy.

Add eggs and egg yolk one at a time, mixing well after each addition.

Gradually add the flour mixture and sour cream mixture to the butter mixture, alternating until just combined.

Fold in the blueberries and finely grated lemon zest.

Spoon the batter into the muffin tins, filling each liner about 3/4 full.

Bake for 16-20 minutes, checking doneness with a toothpick.

Let the cupcakes cool in the tin for 5 minutes, then transfer to a wire rack.

In a mixing bowl, beat the cream cheese and butter until smooth, then gradually add confectioners' sugar and remaining lemon juice.

Once cooled, frost the cupcakes with the cream cheese frosting.