Preheat & Prep: Preheat your oven to 375°F (190°C). Grab an 8x8-inch or similar oven-safe glass baking dish. There is no need to grease it.

Add Peaches: Pour the frozen raw peach slices straight from the bag into the glass baking dish. Spread them out into an even layer, ensuring no massive frozen clumps remain.

Mix Dry Ingredients: In a medium bowl, whisk together the granulated sugar, all-purpose flour, and ground cinnamon until evenly mixed.

Make Crumb Topping: Drizzle the melted butter evenly over the dry mixture. Stir the mixture with a fork until you get a crumbly, sandy texture with small clumps.

Add Topping: Sprinkle this buttery mixture evenly over the frozen peaches in the baking dish.

Bake: Place the dish on the middle rack of the oven. Bake for 35–45 minutes, or until the peaches are tender and bubbling, and the topping is deeply golden brown. (Tip: Loosely tent the dish with foil for the last 10 minutes if the topping is browning too fast).

Rest: Remove the crisp from the oven and let it rest on the counter for at least 10–15 minutes to allow the hot fruit juices to thicken.

Serve & Store: Serve warm with vanilla ice cream. Store any completely cooled leftovers in the fridge for up to 3 days.