Whisk your flour, baking powder and salt together in a medium bowl.
In a stand mixer fitted with the paddle attachment, or in a bowl with a hand mixer, beat the butter and sugar together until it is light and airy.
Add your egg and vanilla extract and beat again on medium-high speed for another minute. Make sure you scrape the bottom and sides of the bowl.
Fold in the dry ingredients, making sure there are no streaks of flour left. Fold in your chocolate chips, and your sprinkles if you're using them.
Scoop out the dough using a cookie scoop, about 2 tablespoons, and roll the dough into balls. Place on a plate or a lined baking tray and chill for at least 2 hours (you can leave up to 3 days though, make sure they are covered with clingfilm).
Preheat the oven to 350°F/175°C. Line two baking sheets with parchment paper and place the chilled cookie dough on the sheets about 3 inches apart. Bake for 12-14 minutes, they should be slightly golden.
Let the cookies cool for 10-15 minutes on the tray before moving to the cooling rack.
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. I have provided a conversion to US cups but please note that I haven’t tested the recipe with this method. Click on 'Metric' above ingredients to get the metric measurements. Butter: I use European style butter, like Kerry Gold, in my recipes. This will make your finished bake much creamier and richer.Storage: keep the baked cookies in a tupperware for up to 5 days at room temperature. Freeze unbaked cookie dough balls, when ready to bake just bake for an extra minute or two.