Using a mixer, mix the room temperature butter on medium speed until fluffy, about 2 minutes. Then add the sugars and continue beating until they come together with the butter as a light fluffy paste (another 3 minutes).
Add the egg yolks and vanilla extract and continue beating until fully incorporated.
In a separate bowl prepare your dry ingredients. Run the flour, baking soda, and salt through a sieve and then mix them with a whisk or a spoon. Also chop up your chocolate bars, aim for 1-2 cm pieces so that you end up with pools of chocolate in some places. The quality of the chocolate you use is incredibly important, so use the highest quality you can get (I like Lindt 70% mild). Please don’t use chocolate chips (ultimately you can, but the chocolate in chips is not the same as in bars, but that’s a story for another day).
With a spoon or a spatula (put the mixer away!), fold in the flour mix until it’s half incorporated. Add the chopped chocolate and continue mixing until the flour is fully incorporated and the chocolate is well distributed.
Cover your dough with plastic wrap and chill it for a minimum of 1 hour - and up to 1 week. I’ve had better results if i baked the cookies the next day, rather than the same day. The dough also can be frozen for up to 3 months. I always freeze cookie dough balls in a ziploc bag and bake them when I need a instant midweek treat.
To bake the cookies: Preheat your oven to 180° C for 15 minutes. Scoop out your dough directly from the fridge, either with an ice cream scooper or a tablespoon. The ice cream scooper helps guarantee hat they are all the same size. Use a tray lined with baking paper and place your dough balls 6 cm apart and bake for 8-12 minutes depending on the size of your cookies. Mine usually are done by the 11th or 12th minute. You are looking for a light golden color on the bottom, that’s your cue for taking them out of the oven. The center SHOULD remain a tad undercooked or else you will not end up with a soft and chewy cookie. Because each oven is different, and different sized cookies need different cooking times, I suggest baking the first cookie alone in order to figure out the right baking time for you. I set the timer for 8 minutes at first and then add more time as needed.
Store your cookies in an airtight container for up to five days - but they won’t last that long. Recipe makes 14-16 cookies. Enjoy!This recipe was inspired by Claire’s cookies from Violet’s Bakery in London, and adjusted to my preferences.