Preheat oven to 350°F. Prepare muffin tin with cupcake papers or reusable liners.
Sift dry ingredients into medium bowl. Transfer 1 tablespoon flour mixture to larger bowl. Add fresh blueberries and toss to coat them with flour. Set remaining flour mixture and blueberries aside.
Stir whole milk, sour cream, vanilla extract, lemon extract and lemon zest in small bowl.
In the bowl of a stand mixer, cream butter and sugar, until pale yellow and very fluffy, about 5 minutes. Beat in eggs one at a time, until well combined. Mix in flour mixture alternately with milk mixture, starting and ending with flour mixture. Stir until just combined. Gently fold in blueberries. Divide batter equally among cupcake cups.
First measure out the 2/3 cup of lemon curd for the frosting and set aside. After the cupcakes are finished cooling, cut a cone shape out of the middle and remove the tops and put a tablespoon or so of lemon curd in the hole. Place the tops back on (you may have to trim the cone a bit to get it to fit). Lather with frosting and enjoy!