Preheat oven to 375 degrees.
Combine the oats and flaxseeds in a food processor, and pulse well until mixture is ground. You may have some whole flaxseeds still, which is fine.
Transfer flour to a medium mixing bowl. Add in cocoa powder, light brown sugar, salt and baking powder. Stir to combine well.
Add in peppermint extract, safflower oil, and 1/4 cup almond milk. Stir together again. Add in more almond milk as needed. Mix in the mint chips.
Spoon batter onto a greased baking sheet, making 15 cookies.
Bake until bottoms are lightly browned, about 12 minutes.