Preheat your oven to 350°F and grease a cupcake pan or using paper cupcake liners

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.

In the bowl of a stand mixer or using an electric mixer, beat the sugar, butter, and vegetable oil together until light and fluffy.

Add the eggs one at a time, beating well after each addition.

Mix in the vanilla extract, and lemon juice.

Alternately add the dry ingredients and buttermilk to the wet ingredients, beginning and ending with the flour mixture. Mix until just combined.

Add the cupcake batter to each muffin tin, only filling about 3/4 of the way to the top

Bake in the preheated oven for 16-18 minutes or until a toothpick inserted into the center comes out clean.

Allow the cupcakes to cool for 30 minutes

LEMON FROSTING

In a large bowl, beat the softened butter until creamy.

Gradually add the powdered sugar, 1 cup at a time, beating well after each addition.

Add lemon juice and beat until well combined.

If the frosting is too thick, add heavy cream or milk 1 tablespoon at a time until the desired consistency is reached.

FILL THE CUPCAKES

Turn the cupcakes upside down and using a small knife, carve a 1/2 inch round circle about 1" deep into the bottom of each cupcake, pulling out the piece of cake you carved out. Using a small spoon or piping bag, fill the centers with jam about 3/4 of the way to the bottom of each cupcake, and then place the piece of cake you carved out back into the hole on top of the jam.