Preheat your oven to 350°F and lightly grease a small oven-safe baking dish or ramekin with avocado oil or coconut oil.
Core and dice the apple and pear into small, uniform cubes, leaving the skin on for extra fiber and texture.
In a medium-sized mixing bowl, whisk together the Greek yogurt, egg, and vanilla extract until the mixture is completely smooth.
Stir in the vanilla protein powder, 0.33 cup of rolled oats, baking powder, cinnamon, and sea salt until a thick batter forms.
Gently fold the diced apples and pears into the batter, reserving a small handful of the fruit pieces for the topping.
Pour the batter into the prepared baking dish and spread it out evenly with a spatula.
Scatter the reserved fruit pieces and the remaining tablespoon of dry oats over the top to create a textured crumble finish.
Bake for 25 to 30 minutes until the center is set and the top is beautifully golden brown.
Allow the cake to cool for at least 5 minutes to let the flavors meld before serving warm.