In a bowl, whisk melted butter with both sugars until glossy.

Add egg and vanilla, whisk until smooth.

Stir in flour, bicarbonate of soda, and salt until a dough forms.

Fold in chocolate chips and half of the M&M’s.

Scoop into large dough balls (about 50–60g each).

Press remaining M&M’s on top for that bakery look.

Bake for 10–12 minutes until edges are set and centres still soft.

Let cool on the tray for 10 minutes before moving.