Preheat oven to 400 degrees F. Line a muffin pan with paper liners or grease with butter.

In a small saucepan, cook the butter over medium low heat until browned, swirling the pan as needed to promote even cooking. Set aside to cool.

In a bowl, sift together the flour, baking powder, baking soda, and salt. In another bowl, combine the browned butter, ¾ cup sugar, and buttermilk. Whisk in the eggs and vanilla extract until smooth. Add to the dry ingredients and stir until just combined. Fold in the blueberries.

Spoon the batter into the prepared muffin pan, filling each cup ¾ full. Bake until golden and a toothpick inserted comes out with dry crumbs, 15-18 minutes. Cool in the pan for a few minutes, then turn out onto a wire rack to cool completely.

Beat together the butter and cream cheese until smooth. Add the powdered sugar, milk or cream, lemon zest, vanilla extract and lemon extract (if using). Beat at medium high speed for 2-3 minutes until light and creamy.

Frost the cupcakes with the cream cheese buttercream. Garnish with fresh blueberries, if desired.

Store cupcakes in the fridge for up to a few days.