Add the brown and white sugar into the bowl with the browned butter. Mix in the egg, egg yolk and vanilla extract. Divide the cookie dough evenly between 3 bowls.
Chop the Christmas Cracker chocolate batons into small chunks.
Fold the milk chocolate chunks into one bowl, the white chocolate chunks into the second bowl and the dark chocolate chunks into the third bowl.
Scoop up heaped tablespoons of cookie dough and toll into balls. Place them on a lined baking tray as you go. You should be able to make 15 in total.
Cover with clingfilm and place into the fridge to chill for at least 1 hour (or up to 2 days if preparing ahead).
Preheat the oven to 180ยบC (fan). Line 2 large baking trays with baking paper.
Place 5-6 cookies on each baking tray, leaving at least 8cm space between each so they have room to spread when baking.
Bake for 10-12 minutes until golden and firm around the edges. The middle should look pale and under-baked - this is a good thing!
Leave the cookies to cool on the baking tray for at least 20 minutes. The cookies will continue to cook and firm up during this time. Now pour yourself a glass of milk and enjoy these delicious cookies!