2: Peel and roughly cube 400 g potatoes, then wash and dry. Set aside.
3: Prepare 400 g green beans, cut into small pieces and cook in a large pot of boiling salted water until tender.
4: Remove them from the water with a skimmer or spider, but leave the water on the heat. Cool under cold water to stop cooking, then drain and dry. Set aside.
5: Pour the potatoes into the same cooking water and cook until just tender.
6: Drain.
7: In a frying pan over medium heat, pour 4 tablespoons oil and when hot, add the potatoes.
9: Add 1 knob butter and the shallot to the pan over medium heat, season with salt and pepper, and cook for 1 minute without browning.
10: Add the green beans...
11: ...and the potatoes and stir to heat through.
12: Pour in 250 g cancoillotte, stir again to warm the cancoillotte, and serve immediately.
Remarks
Green beans and potatoes can easily be prepared and cooked in advance, the day before for example. "Haute-patate" is the nickname given in Franche-Comté (in France) to the department of Haute-Saône, the birthplace of cancoillotte.