Preheat oven to 350°F and line a large baking sheet with a silicone baking mat or parchment paper.
Place 1 cup of the oats and all the other dry ingredients in a large bowl. Whisk to combine.
Make the flax egg by combining the flax seed and warm water in a small bow. Stir and set aside for at least 10 minutes until thickened.
In another bowl, whisk together the remaining wet ingredients.
Stir the flax egg into the wet ingredients then pour into the large bowl with the dry ingredients.
Use a spatula to combine then add the remaining 1/2 cup of oats, raisins and coconut flakes if using to the bowl. Fold in until incorporated with the cookie dough.
Using a small-medium cookie scoop, place dollops of the dough onto the prepared baking sheet.
Use a fork to gently press down the tops as the cookies won't spread much or change shape while baking.
Bake for 10-12 minutes until the edges start to lightly brown.
Remove from the oven and transfer the cookies to a cooling rack.