Whisk together the softened butter and both sugars.
Add in the egg and vanilla extract and whisk until combined.
Then add in the M&M's and fold until combined (reserve a few M&M's for the topping of the cookie).
Sift in the plain flour, baking powder, baking soda and fold until combined.
Use a medium sized ice-cream scoop or roll out 75g dough balls and place into a lined baking tray.
Using the reserved M&M's, place a few on the cookies before baking.
Place into the refrigerator for at least 30 mins to harden.
Then place into a pre-heated oven at 180°C for 14 mins.
