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Sweet Potatoes au Gratin
Cut five medium-sized cold boiled sweet potatoes in onethird inch slices. Put a layer in buttered baking-dish, sprinkle with salt, pepper, and three tablespoons brown sugar, dot over with one tablespoon butter. Repeat, cover with buttered cracker crumbs, and bake until the crumbs are brown.
A two-layer sweet potato bake from Farmer's potato chapter, written for cooks who already had boiled sweet potatoes in the pantry. The original gives no oven temperature and no timing beyond "until the crumbs are brown," so both need filling in.
- Oven temperatureThe original gives no temperature or timing beyond "until the crumbs are brown." A moderately hot oven, around 400F, should colour the crumbs in roughly 20 to 25 minutes, long enough to heat the already-cooked potatoes through; this is a modern reading, not Farmer's instruction.
- The potatoes must be coldBoil and cool them, ideally the day before. Warm sweet potatoes are soft and slump when sliced; chilled ones cut cleanly into the third-inch slices that keep the layers distinct rather than collapsing into a mash.
- "Au gratin" means the crust, not cheeseThe term generally referred to a dish finished with a browned crust, often of crumbs, though many period gratins did include cheese. There is none in this recipe.
- Buttered cracker crumbsCrush plain soda crackers or common crackers to coarse crumbs and toss with melted butter, about 2 tablespoons butter to a cup of crumbs. Panko will work but browns faster and drier.
- Dividing the sugar and butterThe phrasing is ambiguous: the three tablespoons brown sugar and one tablespoon butter may be intended for each layer and repeated, or as the total divided between the two. Either way it is a sweet dish by modern taste, and using less sugar is reasonable.
- Dish size and yieldFive medium sweet potatoes will roughly fill a 1.5- to 2-quart baking dish in two layers and serve about four to six as a side. A wider, shallower dish gives more crumb per portion.
- Salt and pepperThe seasoning is easy to under-do between sugar and butter. Salt each layer properly, and black pepper genuinely belongs here as a counterweight to the brown sugar.
Sweet potatoes appear in Farmer's 1896 potato section as a separate cluster of recipes from white potatoes, reflecting a long-standing American distinction: the sweet potato was a Southern staple that had become a national side dish, particularly in cold-weather and holiday cooking. The technique here, layering a cooked vegetable with butter and browned crumbs, is the plainest form of gratin, with cracker crumbs standing in for the breadcrumbs of French practice. The brown sugar reflects the period's confident treatment of the sweet potato as something between a vegetable and a dessert, the same instinct that produced candied sweet potatoes and, decades later, the marshmallow-topped version.