This thick and chewy cookie is filled with funfetti and milk chocolate chips and then baked in a cake pan to create a twist on traditional birthday cake! Decorated with buttercream and funfetti, it's a fantastic alternative to a bog standard cake!
Preheat the oven to 180C/350F and spray a 9 inch spring form cake pan with cookie spray. I use Wilton Bake Easy.
Place the funfetti, chocolate chips, flour, cornflour, bicarb and salt into a medium sized bowl and stir to coat all the chocolate chips in flour. Leave to one side.
Place the butter and sugar into a large bowl, or the bowl of your stand mixer, and beat on medium high until light and fluffy; 2-3 minutes.
Add in the eggs and vanilla, scraping down the sides as necessary, and mix on medium speed until well incorporated, around 1 minute.
Tip in your flour mixture and the mix on low until a soft dough forms.
Tip the dough into your prepared cake pan and smooth into an even layer with a spatula. Dough will be sticky.
Place in the oven for 25-30 minutes (mine took 27) until golden all over and an inserted skewer into the centre comes out with a few crumbs on it. If you poke the edge, the skewer should come out clean.
Leave to cool completely before transferring to a plate/cake stand.
To decorate: Place the butter and icing sugar into a large bowl and mix with a hand mixer on low until the mixture starts to come together and create small lumps, then add in the vanilla and 1/2tbsp milk.
Continue to mix, increasing the speed to medium-high until the mixture comes together into one ball and then becomes light and fluffy. At this stage add more milk, 1/2tbsp at a time, until you have a smooth, fluffy frosting which holds its shape, but is able to be piped.
Fit a piping bag with an open star nozzle and then fill with the frosting. I held the bag straight above the edge of the cookie cake (not at an angle) and then piped pulling my bag straight up to create little stars.
Sprinkle the frosting with more funfetti and then serve! Funfetti Birthday Cookie Cake will keep covered, at room temperature for 4 days.
This cookie cake is also delicious warm - place a slice in the microwave for 30-40 seconds and then dig in - you can also add ice cream!