Preheat the oven to 180C/160C fan and line two/three large baking trays with parchment paper, leave to the side.
Cream together the butter and both the sugars for two minutes. (I used my electric whisk, if whisking by hand, whisk for 3 minutes)
Add in the vanilla and egg and whisk again until combined.
Add in the plain flour, bicarbonate of soda, salt, cornflour and pumpkin spice and mix until combined.
Now add the white chocolate chips and orange/pumpkin/Halloween M&Ms and beat until everything is evenly distributed and a cookie dough is formed.
Scoop the cookie dough using a cookie scoop for even portions, then roll into balls. Bake in the oven for 10-13 minutes.
Leave the cookies to cool on the trays for 5 minutes, then transfer to a rack to cool completely! Enjoy!
Notes
My homemade pumpkin spice mix is found at the bottom of this page.
I used orange M&Ms as when I baked these and photographed them, I had eaten the pumpkin ones that someone had bought for me. Occasionally M&Ms do ‘special bags’ of Halloween M&Ms so they’d also be good to use.
These cookies can last for three days easily, but they rarely do in my house!
You can easily bake these into cookie bars by following the same method, but baking into a 9″ square tin, and baking for 20-25 minutes at the same temperature!