Preheat your oven to 350 degrees F and line 12 muffin tins with paper liners. 

In a large bowl, whisk together the milk, vegetable oil, eggs, and vanilla.

Add the sugar and whisk to combine. 

Next, add the flour, baking powder, and lemon zest. Mix just until no large lumps of flour remain. 

Divide the cake batter between the muffin tins, filling each one with about ¼ cup of batter. 

Bake for 15-17 minutes, or until a toothpick inserted into the center comes out clean. 

Remove the cupcakes to a wire rack and cool completely. 

When the cupcakes are cool, cut a small circle out of the center of each cupcake (about the size of a quarter). 

Fill each hole with 1 teaspoon of lemon curd and place the cut-out piece of cake back to cover the lemon curd. 

Add the softened butter to the bowl of a stand mixer fitted with the paddle attachment.

Beat on medium speed until the butter is smooth, about 30 seconds. 

With the mixer on low speed, slowly add the powdered sugar. 

Once all of the powdered sugar has been incorporated, add the lemon curd, lemon zest, and vanilla extract. 

Turn the mixer to high speed and beat for 1-2 minutes, or until the frosting is light and fluffy. 

Transfer the buttercream to a piping bag and frost the cooled cupcakes as desired (I’m using a Wilton 2D). Garnish with a wedge of lemon and enjoy. 

Storage: Store any leftover cupcakes in an airtight container in the fridge for up to three days.