Preheat your oven to 360°F (180°C).

In a large bowl, mix the oatmeal, chopped apples, and mashed banana.

Add the water, rinsed cranberries, and raisins to the bowl. Mix well.

Beat the eggs and add them to the mixture along with the baking powder and ground cinnamon (if using). Mix until smooth.

Fold in your favorite nuts.

Pour the mixture into a greased baking dish and spread it evenly.

Bake in the preheated oven for approximately 35-40 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean.

Let the pie cool slightly before serving.

Serve with Greek yogurt and your favorite berries, if desired.