Instructions

To make lemon curd:

1. Melt 1 stick (1/2 cup) unsalted butter in a sauce pan over medium-low heat.
2. Remove from heat and add 1/2 cup lemon juice and 1 teaspoon lemon zest and stir well. Add 3/4 cup sugar, 1 tablespoon cornstarch and pinch of salt to the pan and whisk well. Whisk in egg yolks until smooth and return to medium-low heat. Cook 10 minutes, whisking constantly until the mixture has thickened and coats the back of a spoon (do not allow the mixture to boil!)
3. Separate 5 tablespoon lemon curd and reserve it for the frosting. Set aside to cool completely.

To make the cupcakes:

1. Preheat oven to 350 F, line cupcake pan with paper wrappers and set aside.
2. In a bowl mix the Greek yogurt, milk, vanilla extract and lemon zest, set aside.
3. In another bowl mix flour, baking powder and salt. Take 1-2 tablespoon flour mixture add to blueberries and toss to coat them well.
4. With a mixer, cream 1 stick unsalted butter and 3/4 cup granulated sugar until fluffy.
5. Add egg one at a time to the butter and sugar mixture and mix to combine.
6. Add alternately the milk and flour mixtures ( start and end with the flour mixture).
7. Gently fold in blueberries and transfer the batter into the pan(each cup should be 3/4 full). Tap the pan onto working surface to smooth the batter. Bake for 20 minutes (until toothpick inserted in the center comes out clean. Let them cool for 10 minutes in the pan then transfer to a rack to cool completely.

To make the frosting:

1. Beat heavy cream until soft peaks form, add powdered sugar and vanilla extract and mix until stiff peaks form. Add 1 tablespoon of this beaten heavy cream to lemon curd reserved for filling and 1 tablespoon add to to the lemon curd reserved for the frosting (stir each well with spoon to combine, set aside).
2. In a separate bowl combine the mascarpone and lemon curd (5 tablespoon lemon curd mixed with 1 tablespoon heavy cream) and mix to combine.
3. Add the mascarpone mixture to heavy cream cream and using a spatula gently fold to combine(if you do this with mixer run on a low speed).

To assemble the cupcake :

1. With a cupcake corer or a sharp knife cut out the center and save the tops. Fill the cupcakes with the lemon curd, then place the tops back ( you can trim the tops to make them fit onto the filling)
2. Piped the frosting ( I use 1M tip , but I like to close it a little at the end)
3. Garnished the cupcakes with blueberry, yellow sprinkles and lemon slices.
4. Store in the fridge.