Preheat your oven to 190C/170C Fan and line Two 8″ Circle Cake Tins with parchment paper, and leave to the side for now.
Whisk/Mix the Plain Flour, Cocoa Powder, Bicarbonate, Salt and Cornflour together so its evenly distributed – leave to the side.
In a larger bowl, melt the butter. Add in the two sugars, and whisk for about 2 minutes so the sugar starts to dissolve and the mixture is smooth. Add in the Egg and the Vanilla, and whisk again briefly till smooth.
Add in the Dry Ingredients, the two different chocolate chips, the M&M’s, and mix with a spatula till a thick cookie dough is formed.
Press the mixture into the bottom of the two different tins – I weighed it out so they were the same as it made baking them easier and more even.
Bake in the oven for 25 minutes, until the top of the cookie bake looks ‘dry’ and a skewer comes out basically clean, bar a few crumbs. (Can take up to 30-35 minutes depending on your oven and the mix)
Leave the cookies to cool in their tins for about 10 minutes, then leave to cool fully on a wire rack.
In a stand mixer, beat your butter for a couple of minutes till really smooth and supple. Add in the Icing sugar 1/2 at a time and fully beat in before you add the other half.
Add in the Vanilla Extract and beat the buttercream for about 4-5 minutes until smooth and fluffy. If you think its still a little stiff, add in a couple of tbsps of whole milk, or boiling water and beat till you have the texture you want.
On top of your favourite cookie, pipe little ‘stars’ of buttercream frosting around the edge and sprinkle on some cute sprinkles (like you can see in the pictures).
Spread or pipe the rest of the frosting on top of the other cookie. Put the better cookie with the frosting stars on top and you’re done! Enjoy!
Notes
This delicious recipe is based on a recipe by Crunchy Creamy Sweetwhich I have adapted to grams, and swapped up slightly from my M&M Cookie Bars post to create a double layer cookie cake.
I used oodles of Chocolate M&Ms in this recipe, and the colour on them stayed perfect even after baking, but I’m sure it would work with the Crunchy M&M’s, the Peanut M&M’s, or even smarties for example, and you could just use all chocolate chips, or all M&Ms if you wish – but as I explained earlier on, I liked the mixture.
This amazing Cookie Cake will last for 3 days after baking, but I won’t be surprised if it lasts less than a day.