Preheat the oven to 350 degrees F and line a muffin tin with paper cupcake liners.
Add the butter and sugar to a medium bowl. Beat with a hand-held electric mixer on medium-high speed until light, fluffy, and thick or about 3-5 minutes.
Add in the eggs one at a time, beating in between to fully incorporate each egg. Add in the vanilla.
Add the baking powder, salt, and half of the flour to the bowl. Beat on the lowest speed. Add half of the milk. Beat on the lowest speed. Add the remaining flour and milk and beat on the lowest speed to just combine the batter.
Divide the batter among the paper liners, filling each cup with about 1/4 cup batter.
Bake for 20-22 minutes or until just golden brown around the edges and a cake tester inserted into the center comes out clean.
Remove from the oven. Transfer cupcakes to a wire rack and let cool completely.
Frost as desired.
These are best on the day they are made. If needed, you can make these up to 24 hours ahead of time. Let cool fully and store in an airtight container at room temperature. Frost right before serving if possible.
Store any leftover cupcakes, once frosted, in an airtight container in the fridge for up to 2 days. Let sit for a bit at room temperature before serving to allow them to soften up (the cupcakes firm up in the fridge).
Be sure to beat the butter and sugar for 3-5 minutes until it's fluffy for the best texture results.
To avoid over baking, set your timer for the lower end of the time range and check the centers with a cake tester. If it comes out cleanly, and the edges are lightly golden brown and the tops are firm to the touch, pull them from the oven.
Transfer the cupcakes to a wire rack to cool soon after you pull them from the oven to ensure that they stop baking.
Be sure the butter is soft at room temperature and pull the eggs and butter from the fridge about an hour before you start baking if possible.
It is possible to use plain whole milk Greek yogurt or sour cream in for half of the butter if desired. The results will not be as light and fluffy snd texture-wise, they will be a little less like a classic cupcake.
It is possible to lower the sugar further to 1/3 cup. The texture will not be as light and fluffy and they will be a little less like a classic cupcake.