Buttered Crums

A working component rather than a dish: the buttered crumb topping that finishes scalloped and au gratin dishes. The proportion of butter to crumbs is left to the cook, and that is the only real decision here.

• "Crums"Simply an older spelling of crumbs, common in cookery writing of the period.
• Which crumbsSoft crumbs torn or grated from day-old bread give a light, browned topping; dried crumbs give a crisper, sandier one and absorb more butter. Panko will work, though its coarse flakes behave differently from fine dry crumbs.
• Butter quantityOne tablespoon per cup of soft crumbs gives a dry, loose scattering; three tablespoons gives crumbs that clump and brown evenly into a crust. Two is the safe default for a casserole topping.
• Why not brown the butterThe crumbs are going to brown later, in the oven or under the broiler. Browning the butter first shortens the margin before the topping burns and gives a nutty flavor that may fight the dish.
• Mix off the heatPull the pan from the burner before the crumbs go in, or they toast unevenly and the smallest particles scorch. A fork keeps them separate; a spoon packs them.
• FinishingScattered over a filled dish, buttered crumbs are browned in the oven or under the broiler; the recipe itself gives no temperature or time, so watch them and pull them as soon as they color.
• YieldOne cup of crumbs will roughly cover a 1 1/2- to 2-quart baking dish. Buttered crumbs can be made ahead and kept covered in the refrigerator or frozen, though the recipe gives no guidance on storage.