In a bowl, mix the almond, oat and plain flour, baking powder, baking soda, and salt.
In a separate bowl, mash the banana with a fork, then add the almond milk, maple syrup, vanilla extract, and melted coconut oil.
Mix the wet ingredients with the dry ingredients, then divide the mixture into two. Add matcha to one of them and mix well.
Spoon the batter into the baking tin, alternating between the green and white batter. Use a toothpick to draw swirls to create the marble pattern.
Bake in the preheated oven for 55-60 minutes. It is ready when a toothpick inserted in the center come out clean.
Let it cool on a rack before serving.
