Add in the flour, salt, and chocolate chips. Mix with a spatula or wooden spoon until a soft pliable dough forms. Knead the dough 3 to 5 times bringing the dough together in all.
240 grams plain flour, ½ teaspoon table salt, 75 grams dark chocolate chips, 75 grams milk chocolate chips
Line a 9"x9" square baking tin for a 23cm tart tin with parchment paper. Press the dough into the baking tin. Dock or prick the dough with a fork.
Place the biscuits in the fridge for at least 30 minutes before baking.
Preheat the oven to 180°C/355F and bake the biscuits for 20-30 minutes, until the biscuits are a nice golden brown. Remove from oven and cool on a wire rack before serving.
All temperatures stated are for conventional ovens. Decrease the temperature by 20°C/25°F or gas mark 1 for "fan" or air-fryers.
Notes
Room Temperature butter is essential for this recipe. Remember that room temperature is around 20°C/68F. Butter from the fridge can take up to an hour to reach room temperature (depending on the size of the block of butter).Allow the biscuits to rest in the fridge for at least 30 minutes. This allows the cookies to fully hydrate, for the butter to set, and allows the flavors to fully develop. Resting the dough will also stop the cookies from spreading in the oven during baking.Biscuits can be stored in an airtight container at room temperature for about 2 weeks.