Preheat oven to 350° F and line a cupcake pan with cupcake liners.
In a medium mixing bowl, whisk in the flour, baking powder, and baking soda until fully combined.
In a separate bowl, using either a hand or a stand mixer, cream the butter and sugar together until it is light and creamy. Crack the room temperature eggs into the butter mixture one at a time, and beat together until smooth. Stir in the vegetable oil, fresh lemon juice, milk and lemon zest to the butter mixture.
Slowly begin to pour in the dry ingredients to the wet ingredients and mix it together. Mix this until it is only just combined, do not over mix.
Spoon the batter into the cupcake liners and fill the liners until they are a little over halfway full. Pop them in the oven and bake for about 15 to 20 minutes, or until the top of the cupcake bounces back when you press on it.
Allow the cupcakes to cool completely. Once cooled, use a cupcake scoop or spoon to remove the middle of the cupcake. Using either a spoon or a piping bag, fill the centers of the cupcake with the premade lemon curd.