Start by sieving your flour into a baking bowl to get rid of lumps. Now, add your baking powder to the flour. In another bowl, add your butter. Next, add your sugar.
Mix your batter for about 7-10 minutes till it gets fluffy. Now, add your eggs one by one and mix as you go. Now, add your vanilla extract gently into the mix. After that, gradually add the flour and the milk while you're still actively stirring the batter.
Try not to overmix and after you're done adding the flour and the milk, scrape the sides of the bowl to get all the remnants of the flour together. Stir with your spatula to even them out.
Transfer the batter into an oiled and floured loaf pan or baking pan. Evenly flatten the batter out in the pan. Now, place in a preheated oven at 180 degrees celsius for 55 minutes to 1 hour.
After the time has elapsed, you can take it out to see how beautiful your cake turned out. Your cake is ready to be served after it has cooled down.