Position a rack in the middle and preheat the oven to 375°F (190°C).

In a large deep skillet, melt half of the salted butter over medium heat. Add half the peaches and cook, tossing occasionally, until browned and fragrant, about 5 minutes. Transfer to a bowl and repeat with the remaining salted butter and peaches.

Return the all the peaches to the pan, pour in the beer, and simmer until the beer has almost evaporated, 10 to 15 minutes. Transfer the peaches to a 9-inch (23-cm) square baking dish.

In a large bowl, combine the rolled barley or oats, unsalted butter, and honey. Use your hands to press and pinch together the ingredients to form a crumble. Sprinkle the crumble evenly over the peaches.

Bake until golden brown, 20 to 25 minutes. Cool slightly on a wire rack.

Serve the crumble warm, topped with ice cream, if you like. Leftover crumble will keep, covered and refrigerated, for 2 days. Serve cold or at room temperature, or gently reheat in a low oven.