Jansson's Temptation

Serves 4 to 6

2 ¹/2 lbs. yukon gold potatoes (about 5 medium potatoes)
2 Tbsp. butter
1 medium onion, minced
16 anchovy fillets (highest-quality oil-cured fillets come in glass jars)
¹/2 c. cream
1 ¹/2 c. evaporated milk
1 tsp. salt
¹/2 tsp. fresh ground white pepper

Adjust oven rack to middle position; heat oven to 425º F. Peel the potatoes and slice into fingers Ľ to ˝ inch thick. Cover with water until needed. Melt butter in a large dutch oven over medium-high heat until foaming subsides. Add onion and cook, stirring occasionally until soft and lightly browned. Add anchovies and dissolve them a little. Drain potatoes and add. Add remaining ingredients. Bring to simmer. Cover, reduce heat to medium-low, and simmer until potatoes are almost tender, about 10 minutes--stir seldom to avoid breaking potatoes. Transfer mixture to a 1 or 1˝ quart gratin dish. Bake until bubbling around edges and top is golden brown, about 15 minutes. Cool 10 minutes before serving.