Preheat your oven to 350F and line a standard-size cupcake tin with cupcake liners (this recipe makes 12 cupcakes).
In a medium bowl, combine 1 ½ cups flour, 1 teaspoon baking powder and ½ teaspoon salt. Set aside.
Using an electric mixer or a stand mixer fitted with the paddle attachment, beat ¼ cup butter and 2 ounces cream cheese on medium speed for about a minute then add the 1 cup of sugar. Beat for another 2 minutes or until light and creamy.
Add the 3 eggs one at a time making sure it's combined well each time.
Then add the 2 tablespoons of limoncello. Remember to scrape the bottom and sides of your bowl.
Switch to low speed and add a third of your flour mixture. Then half of your buttermilk. Add another third of the flour, the rest of the buttermilk and finally the rest of the flour.
Mix in the ¼ cup lemon juice and ½ teaspoon lemon zest just until combined. Again, scrape the bottom and sides of your bowl for any rogue batter
Scoop your batter evenly into your tins (about ¾ full).
Bake for 20-30 minutes or until a toothpick inserted comes out clean.
Remove from the oven and let cool in the pan for about 10 minutes. Then move to a cooling rack to cool completely.
Limoncello Cream Cheese Frosting:
Using an electric mixer or a stand mixer fitted with the paddle attachment, beat the ¼ cup butter and the 6 ounces cream cheese on medium speed for about 4-5 minutes or until light and fluffy.
Add the 1 tablespoon limoncello and beat just until incorporated.
Switch to low speed and gradually add the 2 cups of confectioner's sugar. Add a little bit more at a time until you get the consistency and the level of sweetness you prefer. Beat until smooth and creamy.
Make sure the cupcakes are completely cool.
Using a small knife, carve a small hole (about an inch in diameter and an inch deep) into the middle of your cupcake.
Take the extra cake out and fill the hole with a dollop of lemon curd. Don't put too much curd; just put enough so that it's level with the top of your cupcake.
Frost and decorate as desired.
If using homemade lemon curd, make it a day ahead because it needs to chill before you can use it.