Peel and slice 6 raw potatoes very thin; then beat 1 egg with 1 tablespoonful of butter. Put the potatoes into a shallow baking-dish, sprinkle well with salt and pepper. Add enough milk to cover the potatoes; add the beaten egg. Sprinkle ½ cup of grated cheese over all and let bake until done.
June 23 — No. 23
Scotch
A plain gratin: raw potato in milk under cheese, with an egg to set the custard. The original gives no oven temperature and no time, so both need supplying.
- Oven and timingBake at 350F for 60 to 75 minutes, covered for the first 40 minutes and uncovered after that to brown the cheese. "Until done" means a knife slides through the centre with no resistance; undercooked potato in the middle is the usual failure here.
- Slice thickness"Very thin" is about 1/8 inch — a mandoline or the slicing blade of a food processor is worth using. Uneven slices cook unevenly and the thick ones stay chalky while the thin ones dissolve.
- Temper the eggWhisk the egg with the melted butter and then with a few spoonfuls of the milk before pouring it over, otherwise it sets in threads rather than binding the milk into a custard.
- How much milkFor 6 medium potatoes in a shallow dish, expect 1½ to 2 cups. The recipe says milk enough to cover; if you want the cheese to brown, keep the liquid at or just below the top layer rather than well over it.
- Potato varietyA starchy, floury potato such as a russet thickens the milk as it cooks. Waxy potatoes hold their shape but leave the liquid thin.
- The cheeseThe recipe says only "grated cheese"; a firm cheddar suits it. Half a cup of grated cheese is a modest amount by current habit; a full cup is not out of place.
- CurdlingWhole milk under a hot oven can break. Keeping the temperature at 350F rather than higher, or replacing part of the milk with cream, keeps it smooth.
- YieldServes roughly 4 to 6 as a side dish, depending on the size of the potatoes.
Potatoes baked in milk under cheese belong to the wide family of scalloped and gratin dishes common in British and American home cooking in the nineteenth century. Calling the version "Scotch" reflects the habit, common in books of this sort, of pinning a national label on a dish by way of a single characteristic ingredient — here a hard, sharp cheese, together with the reliance on potatoes as a daily staple after their spread through Scottish agriculture in the eighteenth century. Such attributions should be read as a period gesture rather than evidence of a Scottish original.