Literally called “potatoes from the baker,” boulangère potatoes (or pommes boulangère) originated in France centuries ago when people in rural areas did not own ovens of their own. On their way to church, women would take the Sunday roast of lamb in a dish, surrounded with sliced onions and potatoes, to the baker to be cooked in his oven while the family prayed. Afterward, they picked it up and took it home for lunch, perfectly done. This boulangère potatoes version comes from Maurice Moore-Betty, a popular cookbook writer and teacher during the 1960s and ‘70s. Boulangère potatoes can be used as a side dish to go with pork or beef or lamb, or as a main dish if you feel like having a light meal or if you are following a vegetarian diet.
Heat oven to 200°C/fan 180°C/gas 6. Fry the onions and thyme sprigs in the oil until softened and lightly coloured (about 5 mins). Spread a layer of potatoes over the base of a 1.5-litre oiled gratin dish.
Sprinkle over a few onions (see picture, above) and continue layering, finishing with a layer of potatoes. Pour over the stock and bake for 50-60 mins until boulangère potatoes are cooked and the top is golden and crisp.