Preheat oven to 375º F.
Line the cupcake tins with paper liners.
Cream the butter and sugar until light and creamy.
Combine the flour, baking soda, baking powder, and salt in a separate bowl.
Add one egg at a time to the butter and sugar mixture, beating after each egg has been added.
Add the lemon extract and lemon zest to the butter, sugar, and egg mixture.
Add 1/3 of the dry mixture to the wet mixture while continuing to mix.
Add 1/2 of the milk, mix.
Add 1/3 of the dry mixture, mix well.
Add the last 1/2 of the milk, mix.
Add the last 1/3 of the dry mixture and mix well.
Make sure all ingredients are thoroughly blended.
Scoop the batter into the paper-lined cupcake tins until they are 3/4 of the way full.
Bake at 375º for 15-17 minutes or until an inserted toothpick comes out clean.
Cool for 10-15 minutes.
Remove from the cupcake tin and cool on wire racks until completely cool to the touch.