Take the butter of out the fridge 20-30 minutes before using and leave it to soften. If you don’t have much time, zap it in the microwave in 20-second flashes on MEDIUM.
Preheat your oven to 180°C/350°F.
In your food processor, cream together the butter, sugar(s) and salt.
Add the vanilla and egg, and mix until fully incorporated.
In a bowl, whisk together the flour and baking powder, and add to the butter mix in 4 batches (about 4 tablespoons at a time). Do not hesitate to open the processor and scrape down the sides.
Last, add the chocolate chips at slow speed so they don’t melt.
Using a spoon or ice cream scoop, form balls and place them on a baking paper-lined baking sheet. The ice cream scoop helps creating even-sized cookies that will bake more evenly.
Bake for about 10 minutes, or until the edges start browning.
Cool on a wire rack before diving in.