Preheat your oven to 175°c. Grease or line a cake pan with parchment paper. In a mixing bowl, combine the rolled oats and skimmed milk. Let it sit for about 10 minutes to allow the oats to soften. After 10 minutes, add the eggs, honey or maple syrup, and vanilla extract to the oats mixture. Mix well to combine. In a separate bowl, whisk together the baking powder, ground cinnamon, and salt.  Gradually add the dry ingredients to the wet ingredients, mixing until well
incorporated. If desired, fold in any optional add-ins such as chopped nuts, dried fruits, or shredded coconut. Pour the batter into the prepared cake pan and spread it out evenly. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean Once baked, remove the cake from the oven and allow it to cool in the pan for a few minutes before transferring it to a wire rack to cool completely.