Preheat the oven to 350° F.
Combine the flour, protein powder, coconut sugar, baking powder, and baking soda in a large mixing bowl.
Add the melted coconut oil and nut milk.
Mix again until a thick and sticky cookie dough forms.
Gently fold in the rainbow sprinkles.
Divide the dough into 12 equally sized pieces.
Roll each piece of dough into a round ball.
Place the cookie dough balls on a lined or greased baking sheet, leaving space between each one.
Bake the cookies for about 6-8 minutes, press them flat with the back of a rubber spatula, then bake them for another 1-2 minutes, or until golden brown.
Let the cookies cool completely (they will firm up during this time), then dig in and enjoy!