Prepare the peach: Dice 1 peach, finely diced finely and place in a small bowl. Add 1 tablespoons maple syrup (or any sweetener) and toss to coat. Let sit for a few minutes while preparing the topping.
Mix the dry ingredients: In a separate small bowl, combine 3 tablespoons oat flour, 1 tablespoons walnuts, crushed, 0.5 tablespoons brown sugar, 1 pinch salt, 0.1 teaspoons ground cinnamon, and 0.5 teaspoons baking powder. Stir until evenly mixed.
Add the milk: Pour 2 tablespoons milk into the dry ingredients and stir until a thick, slightly crumbly batter forms.
Assemble: Transfer the sweetened peach into a small oven-safe baking dish or ramekin. Spoon the oat topping evenly over the peaches.
Bake: Set your oven to 375°F and let it fully preheat, Bake for 35 to 45 minutes, keeping a close eye on the crisp as it bakes to watch for burning. It should be golden and bubbly when done.
Cool and serve: Let cool for a few minutes before serving. Top with 1 vanilla ice cream, for serving (optional, scoop) if desired.