Preheat and prepare: Start by preheating your oven to 350°F (175°C). Lightly grease your baking dish with oil or cooking spray.

Mash the banana: In a large bowl, mash the ripe banana until completely smooth.

Whisk the wet ingredients: Add the eggs, honey, milk, and vanilla extract to the mashed banana. Whisk until everything is well combined and the mixture is smooth. An electric hand whisk is useful for this step.

Add the dry ingredients: Stir in the oat flour, rolled oats, protein powder, baking powder, salt, cinnamon, nutmeg, and ginger. Mix until fully combined.

Fold in the carrots and extras: Add the grated carrot and any optional mix-ins like raisins, walnuts, or coconut. Gently fold them through the batter so they’re evenly distributed.

Bake: Pour the mixture into your prepared dish and spread it out evenly. Bake for 25 to 30 minutes, or until the top is golden and a toothpick inserted into the center comes out clean. If using an 8x8 inch cake pan you may need to bake for an additional 5-10 minutes.

Wile the oats are baking make the frosting: In a small bowl, whisk together the Greek yogurt, softened cream cheese, honey, and vanilla until smooth. Again, use an electric hand whisk if you have one.

Cool before frosting: Allow the oats to cool in the dish for at least 20 minutes and loosen the edges with a knife. This allows the oats to further firm up and this step is key so the frosting doesn’t melt when you add it.

Frost and finish: Once the oats are cool, spread the frosting evenly over the top. Sprinkle with chopped walnuts or any extra toppings you like. Slice into squares and enjoy.