Preheat oven to 180°C (350°F) and line a baking tray with parchment paper.
Mash the banana in a bowl until smooth with minimal lumps.
Add grated carrot and mix until moisture spreads evenly.
Crack the egg into the mixture and stir until a slightly thick batter forms.
Add rolled oats and oat flour, stirring slowly to avoid clumps. If dough feels too dry, add water 1 tablespoon at a time until a soft, workable dough forms.
Scoop small portions and roll into balls or flatten slightly. Keep size consistent for even baking.
Place treats on the prepared baking tray and bake for 18–22 minutes until lightly golden.
Cool completely before serving to your dog. Store in an airtight container at room temperature for up to 3 days, or refrigerate/freeze for longer storage.