For the crust:

  • Butter, for coating the baking dish
  • 1 cup  gluten-free rolled oats
  • 1 cup  almond flour or almond meal
  • 3/4 cup  packed light brown sugar
  • 1/2 cup  sliced almonds
  • 1/2 teaspoon  fine salt
  • 8 tablespoons  (1 stick) unsalted butter, melted and cooled

For the topping:

  • 1/2 cup  granulated sugar
  • 1 tablespoon  cornstarch
  • 6 cup  sliced fresh peaches (about 1 pound of slices from 6 large peaches)
  • 1 tablespoon  freshly squeezed lemon juice

Make the crust:

  1. Arrange a rack in the middle of the oven and heat to 350°F. Coat a 9×9-inch glass baking dish with butter.

  2. Place the oats, almond flour or meal, brown sugar, almonds, and salt in a large bowl and stir until combined. Drizzle the butter over the oat mixture and stir to combine. Press about 1/2 of the oat mixture into the prepared baking dish.

Make the filling:

  1. Place the granulated sugar and cornstarch in a medium bowl and stir until lump-free. Add the peach slices and lemon juice and gently toss to coat. Transfer the peach mixture onto the prepared crust.

  2. Crumble the remaining oat mixture onto the fruit, pressing it into clumps if desired. Bake until the oat topping is golden and the fruit is bubbling, about 1 hour. Cool for 20 minutes and serve with ice cream or vanilla butter sauce.