Pour your desired amount of oat milk into a mug and heat in a microwave for about a minute. Alternatively, you can heat in a saucepan on the stove if that suits you as well. In a blender, combine the matcha powder, collagen powder, and maple syrup. Once the oat milk is finished heating, add it into the blender as well. Blend all ingredients for roughly 20 seconds. Pour into a mug to enjoy hot OR pour into a tumbler and load the rest of it with ice cubes to enjoy cold.