First, preheat the oven to 365°F and cover a baking tray with parchment paper.
In a large bowl, mix the milk, oil, and Stevia; then combine the sifted flour with the baking powder and the rolled oats.
1/3 cup oat milk (or normal milk), 1/3 cup + 1 tbsp sunflower oil, 1/2 cup stevia sweetener (not the liquid one, but the one with sugar-like grains; if calories are not an issue, regular sugar is fine), 1 cup and 4 tbsp whole-wheat flour (or oat flour for gluten-free), 1 tsp baking powder, 1 1/2 cup rolled oats
Mix all the ingredients with your hands until you get a rather rustic-looking dough that is similar to shortbread.
Shape the dough into small balls, mine were 25g each, and place them on the baking tray. The total cooking time for the cookies is about 25 minutes but set a timer at 10 minutes, and press the balls with a fork or spatula as they bake to flatten them to the desired thickness. If you want to get "chunkier" disks like mine, just press gently.
Bake the cookies until golden, but let them cool on the baking tray before gently transferring them to a cookie tin. Do not overbake, since these cookies dry very easily.