Line a baking sheet with parchment paper. Set aside.
In a medium microwave-safe bowl, add in the butter.
Microwave the butter for 20-25 seconds, until the butter is partially melted.
Add in the coconut sugar and granulated sugar and whisk until combined with the butter.
Next, add the egg yolk and vanilla extract into the bowl and whisk until lightened and incorporated.
Add in the all-purpose flour, baking soda, rolled oats and almond flour.
Use a spatula to gently combine the dry ingredients with the wet ingredients.
Add in the M&Ms and fold it into the cookie dough using the spatula.
Use a 1 tablespoon cookie scoop to scoop the dough onto a lined baking sheet.
Place the cookie dough into the fridge or freezer to chill for 30 minutes.
Preheat oven to 350°F/177°C.
Arrange the cookie dough onto a lined baking sheet with at least 2" in between.
Bake the cookies at 350°F/177°C for 9-11 minutes, until slightly puffed up.
Remove the baking tray and carefully bang it on a counter once or twice to flatten (if you prefer a less puffy cookie).
Let cool on the cookie sheet for 5 minutes before carefully transferring to a wire rack to completely cool.