Line a 12-cup muffin pan with cupcake liners.

In a large bowl, whisk the flour, baking powder, and salt together. Set aside.

In a separate large bowl, beat the butter, sugar, and lemon zest on medium-high speed for about 3 minutes until creamy. Scrape down the sides and bottom of the bowl as needed.

Add eggs and vanilla extract to the butter mixture. Beat on medium-high speed for 1 minute, scraping down the bowl as needed.

Gradually add the dry ingredients to the wet mixture, mixing on low speed. Slowly pour in the milk and lemon juice while mixing until just combined.

Gently fold in the floured blueberries until evenly distributed. Do not overmix.

Spoon the batter into the cupcake liners, filling each about ⅔ full.

Bake for 18–21 minutes, or until a toothpick inserted in the center comes out clean.

Let the cupcakes cool completely before frosting.

Beat the cream cheese and butter together on medium speed for about 2 minutes until smooth.

Add the confectioners’ sugar, vanilla extract, and salt. Beat on low for 30 seconds, then increase to medium-high speed and beat for 2 minutes. Taste and add more salt if needed.

Frost the cooled cupcakes with the cream cheese frosting and garnish with lemon slices and extra blueberries, if desired.

Refrigerate decorated cupcakes uncovered for at least 20 minutes to set the frosting before serving.