In a medium bowl whisk together the flour and baking powder. Set aside
In your stand mixer with paddle attachment beat together unsalted butter and sugar until well combined.
Add in egg and mix well again,
Then add in the vanilla.
Start adding the flour mixture a cup at a time.
Mix until dough forms and begins to clump together.
Gather up the dough and knead it with your hands until it’s nice and smooth.
Roll it into a ball, wrap it with plastic wrap, and place in the fridge to chill for about 20-40 minutes.
Preheat oven to 350ºF and butter a 12 muffins pan.
Get your cookie dough and make small balls, about a tablespoon full.
Put them into each muffin hole and press them against the bottom to the sides.
If you think it needs more dough you can adjust the amount.
Bake for about 10-15 minutes.
The dough tends to grow a bit and lose the cup shape, don’t panic that’s normal. Once they are done, just re-do the shape using a smaller cup (smaller than the muffin hole) or a species bottle as soon as you take them out of the oven. That way they keep the shape as they set.
Let them cool completely.