Line a standard 12 cup muffin tin with paper liners.
In a medium bowl, sift the cake flour, baking powder and salt.
In a large bowl, combine the butter and oil.
Whisk in the sugar.
Whisk in the eggs, one at a time. Mix until just combined.
Add the vanilla and lemon zest. Mix to combined.
Add the flour mixture and milk alternating between the two in three additions, starting and ending with the flour mixture.
Fill each cupcake liner about 2/3 full.
Bake for about 20 to 24 minutes or until a toothpick inserted in the center comes out clean.
Allow the cupcakes to cool in the tin for about 15 minutes. Remove the cupcakes and allow them to cool completely before assembling.
For the Vanilla Frosting:
In the bowl of a mixer fitted with a paddle attachment, beat the butter and sugar until light and fluffy.
Add the lemon extract and salt. Mix until combined.
Add the cream and beat until fluffy.
To Assemble the Cupcakes:
Using a sharp paring knife, cut a circle that's about 1-inch in diameter at the top of each cupcake. Remove the cut piece, and fill with 1-2 teaspoons of lemon curd. Replace the top of the cupcake over the lemon filling.
Using a piping bag fitted with a large round tip, pipe the frosting on the cake.
Notes
The calories shown are based on the recipe making 12 cupcakes, with 1 serving being 1 cupcake. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information.**