225g butter 200g brown sugar 100g white sugar 1 large egg 1 tsp vanilla extract 6g salt 205g 550 flour 2.5g baking powder 2.5g baking soda 250g cornflakes 125g chocolate chips 65g mini marshmallows

Place cubed butter with the sugars in a food processor fitted with a paddle and mix for 3 minutes. Clean the edges with a spatula and add the egg. Continue mixing for 7 minutes, cleaning the rim occasionally. The time is important, you want to get plenty of air in the mixture so that when you bake the cookies you don't have the problem of them being too flat and the butter melting.

Add the vanilla extract and salt and mix them in.

Now add the dry ingredients, flour, baking soda and baking powder, mix only until the dough is almost homogeneous, so only 15 seconds. Remove the dough from the side of the bowl.

Crush the cornflakes a little bit with your hand and add them with the chocolate chips and the marshmallows to the dough. Mix just briefly.

Chill the dough for at least 2 hours. The longer/colder, the better.

Portion the cookies with an ice cream scoop and place them on a baking tray with a good distance between them - covered with a silicone mat or baking paper.

Preheat the oven to 200 degrees and bake the cookies for about 7-10 minutes. Let them cool and enjoy.