Lemon Blueberry Cupcakes

INGREDIENTS

For the cupcakes::

1 3/4 cups

all-purpose flour

1 tsp

baking powder

1/2 tsp

baking soda

1/2 tsp

salt

1 stick

unsalted butter, at room temperature

1/2 cup

granulated sugar

1/4 cup

lightly packed brown sugar

large eggs plus one egg yolk, at room temperature

1 cup

buttermilk

lemons, zested and juiced

3/4 cup

fresh blueberries

2 tbsp

all-purpose flour

For the buttercream::

3/4 cup

fresh blueberries

3 cups

powdered sugar, sifted

2 sticks

unsalted butter, at room temperature

1/4 tsp

fine salt

2 tsp

pure vanilla extract

to 2 tablespoons heavy or whipping cream

Lemon zest, for garnish