If making these with brown butter (it adds major depth of flavor): start by placing the butter in a pan on a low/medium heat. Stir and swirl the pan while heating for about 5-7 minutes, until the butter has browned and looks foamy. Remove from the heat and immediately pour into a bowl to prevent the butter from burning.
In a large bowl, using an electric/stand mixer combine the butter and both sugars on medium speed for several minutes, until fully combined. Add the egg and vanilla and mix again.
Add the flour baking powder and mix until combined. Finally mix through the mini chocolate chips. The dough should be fairly solid at this stage, but still pliable. Place in fridge to chill for 15 minutes.
Preheat the oven to 175℃/350℉. Line two to three large baking sheets.
Roll balls of dough - use less than half a teaspoon and roll to make mini cookie dough balls. These should be about 1/4 inch diameter or less. Place on a baking sheet, they do not spread that much so you can place fairly close together.
Bake 7-8 minutes, until they look just cooked and lightly golden. Remove from the oven. You can press down each cookie just a little using a spoon if they are still too 'ball-like'. Let cool before removing from the tray to bake the next batch. If placing multiple trays in the oven at the same time, keep an eye on each tray as they will bake at slightly different times depending on your oven.
Once all cooled, place the cookies in mason jars and wrap with ribbon if gifting. Otherwise, keep stored in an airtight container!