Preheat the oven to 350°F. Butter and flour three 6-inch round cake pans.

Beat together the wet ingredients in a medium bowl. Set aside.

Sift the dry ingredients together in a medium bowl. Toss the blueberries with a tablespoon of flour and set aside.

In a large mixer bowl, beat the butter until creamy. Add the flour mixture and mix until sandy.

Slowly pour in the wet ingredients and mix until just combined. Fold in the flour-coated blueberries.

Divide the mixture evenly into the cake pans.

Bake for about 30 minutes or until the centers spring back when touched. Let cool for 15 minutes.

Place ½ cup blueberries in the freezer.

In a saucepan over medium-low heat, combine remaining blueberries, sugar, lemon juice, and water. Cook until berries start to burst.

Mash and stir for a minute, then simmer until reduced by half. Strain the liquid and chill.

In a mixer bowl, beat the butter and salt until fluffy. Gradually add in the confectioners’ sugar.

Beat in lemon juice until desired consistency is reached.

Mix blueberry reduction into a portion of the frosting to flavor it.

Prepare piping bags with the flavored and unflavored buttercream.

Pipe a ring of lemon buttercream around the edge of one cake layer and fill with blueberry-lemon buttercream.

Top with another layer and repeat. Smooth more lemon buttercream around the sides and top.

Pipe dollops of lemon buttercream around the edge and add blueberries.

Refrigerate for 20 minutes before slicing.