Leave butter out until it reaches room temperature

Preheat oven to 375°F

Line 30 cupcake pans with paper liners

Sift the self-rising four and salt together in a bowl

In another bowl, beat the unsalted butter and sugar with an electic mixer until light and fluffy

Beat in the eggs one at a time into the butter mixture, beating each egg until incorporated before adding the next

Mix in the vanilla extract and lemon zest into the butter mixture.

Gently beat the flour mixture into the butter mixture, one third at a time, alternating with half the milk and half the lemon juice after each of the first 2 additions of flour.

Beat until just combined; do not over mixe

Fill the prepared cupcake liners with batter 3/4 full

Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 17 minutes.

Let the cupcakes cool in the pans for about 10 minutes before removing them to finish cooling on a rack.