Line a baking sheet with parchment paper.

Add the chocolate chips to a microwave-safe bowl and heat in 30-second intervals, stirring after each, until fully melted and smooth.

Spoon the melted chocolate into a piping bag or a zip-top bag, then snip off a small corner.

Arrange the Biscoff cookies evenly on the prepared baking sheet.

Pipe the melted chocolate in a zigzag motion above each cookie to create a Christmas tree shape.

Press mini M&M’s gently onto the chocolate before it sets to look like ornaments.

Place the tray in the refrigerator for 15 minutes, or until the chocolate has hardened.

Once set, remove the cookies from the fridge and carefully lift them from the parchment paper. Serve immediately or store in an airtight container until ready to enjoy.