Place the softened butter and sugar into a mixer bowl and whisk on medium to high speed until light and fluffy, about 4 minutes. Add the eggs and whisk for another 2 to 3 minutes, until well combined. Combine flour and baking powder in a separate mixing bowl. Add approximately half of the milk and flour in the cake batter and mix using whisk attachment. Add remaining milk and flour by hand, folding in carefully to avoid over-mixing. Add the blueberries, the lemon zest and lemon juice and stir in just until combined.

Fill each cupcake about three-quarters of the way full. Bake in preheated oven until tops are golden brown and toothpick comes out clean, about 23 to 26 minutes. Remove the cupcakes from pan and let cool completely on a wire rack before frosting.

For the frosting: place the cream cheese into a large mixing bowl and whisk for a few minutes on high speed until light and fluffy. Add the chilled heavy cream, sugar and lemon zest and continue whisking on high speed for 3 to 4 minutes, until stiff peaks form. Transfer the frosting into a pastry bag and decorate the cupcakes. Garnish with more lemon zest or sugar crystals. Store the cupcakes in the refrigerator when not enjoying.