Preheat oven to 350°. In a food processor, pulse the pitas, torn into large pieces, and the almonds until coarsely ground. Transfer to a medium bowl. Add the unsalted butter, melted, the dark-brown sugar, the granulated sugar, the coarse salt, and the ground cinnamon; toss to coat.

Transfer mixture to a large parchment-lined rimmed baking sheet and bake, stirring occasionally, until golden and crisp, 10 to 12 minutes. Let cool on sheet on a wire rack. (Store in an air-tight container, at room temperature, up to 4 days. Serve streusel sprinkled over ice cream, yogurt, or oatmeal.