1.Preheat the oven at 190° Celsious and line a 24 muffing tin with cupcake cases. Mix together the flour, baking powder and salt in a bowl and set aside. In a jug, combine the beer and milk and set aside too.
2.Using an electric mixer, cream butter and sugar together for 2 to 3 minutes until they are light and fluffy. Add the eggs, one at a time, and mix well between additions. Add the vanilla essence and lemon zest and mix well.
3.Add a third of the dry ingredients to the batter and while whisking at low speed, pour half of the beer and milk liquid. Whisk until all ingredients are incorporated. Repeat this step again. Finish up by adding the last third of the flour and whisk until your batter is all combined.
4.Fill the cupcake liners two thirds full and bake for 20 minutes or until a cake tester comes out clean. This cupcakes are not suppose to be too brown, so don't worry if they look a bit pale. When they are done, take them out of the oven.
5.While they are still hot, make a few holes all over the top of the cupcake with a toothpick. Then, using a pastry brush, varnish the top of the cupcakes generously with the extra 1/4 cup of beer from the ingredients. This will flavour the cupcakes even more and keep them moist for longer. Once varnished, they can be let cool down on a wire rack. While they cool, prepare the lime cheese icing.
6.The Lime Cheese Icing is very easy to make. Cream the cheese and butter together with an electric mixer until smooth. Add the lime juice and zest and gradually add the icing sugar while constantly whisking/mixing until all ingredients are well combined, about 2 minutes. Your icing is ready!