Preheat your oven to 350°F (175°C).

In a medium bowl, whisk together the gluten-free all-purpose flour, baking soda, and salt.

In a large bowl, cream the softened unsalted butter, brown sugar, and granulated sugar together until light and fluffy, about 2-3 minutes.

Add the egg and vanilla extract to the butter and sugar mixture and beat until well combined. Gradually add the dry ingredients to the wet mixture and mix until just combined.

Gently fold in the M&M candies until evenly distributed.

Scoop the dough onto a prepared baking sheet, spacing the cookie dough balls about 2 inches apart.

Bake for 10-12 minutes until the edges are lightly golden and the centers remain soft. Allow to cool on the baking sheet for 5 minutes before transferring to a wire rack.