Preheat the oven to 350°F (180°C) fan.
Make the flax egg by mixing the ground flaxseeds with the water. Let it sit for at least 5 minutes until a gel forms.
In a bowl, combine the almond flour, protein powder, baking soda and a pinch of salt (see step-by-step pictures in post above).
If your coconut oil is solid, melt it for 15 seconds in the microwave on defrost function. That way, the coconut oil will be melted but not too hot.
In a larger mixing bowl, whisk the melted coconut oil and the coconut sugar. Add in the vanilla extract and the plant-based milk.
Add the dry ingredient to the wet ingredients and stir to combine. You don't need to chill the cookie dough.
Scoop cookie dough balls onto a cookie sheet that you lined with parchment paper using a 2 tablespoons cookie spoon. Press it flat with the palm of your hand until it's about 0,6 inches (1,5 cm) thick.
Bake the cookies for 8 minutes until golden brown.
Let the cookies cool down on the baking sheet for 10 minutes before transferring them to a cooling rack. Let them cool completely before eating.