For the cake batter: Preheat the oven to 350 degrees F. Line a standard cupcake or muffin pan with 12 cupcake liners.
Combine the flour, baking powder, salt and baking soda in a small bowl and set aside. Combine the granulated sugar and butter in the bowl of stand mixer with a paddle attachment and mix on medium speed until creamy. While the mixer is running, add the eggs and yolks one at a time, thoroughly mixing after each egg. Alternate adding the flour mixture and sour cream, ending with the flour. Add the coconut milk and coconut extract and mix on medium speed until the ingredients are all fully incorporated.
Fill the liners three-quarters full with the batter and bake until cooked through, about 20 minutes. Cool the cupcakes completely before frosting.
For the blueberry filling: In a small bowl, mix together 1/4 cup water and the cornstarch. In a small saucepan, combine the blueberries, granulated sugar, lemon juice and the cornstarch mixture. Mash the ingredients together with a potato masher, strain through a sieve and return the strained portion to the saucepan. Cook on medium heat, stirring constantly, until bubbling and thickened, about 5 minutes. Set aside to cool completely.
For the coconut cream cheese frosting: Beat the butter in a stand mixer or with a hand mixer until creamy. Add the cream cheese and continue to beat until fully combined and smooth. Add the confectioners' sugar, heavy cream, coconut extract, coconut milk and salt and mix until light and fluffy and piping consistency.
To assemble: Cut out a hole in each cupcake and fill with some of the blueberry filling. Frost with the coconut cream cheese frosting.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.