What makes Dauphinoise different from scalloped potatoes?
Dauphinoise is typically baked in cream (and often garlic) and usually does not include a flour-thickened sauce. Scalloped potatoes are often made with milk and may use a thickened sauce, though recipes vary. This one is all about that silky cream soaking into the slices.
Do I need cheese?
Traditional Dauphinoise does not require it. That said, a small handful of Gruyère on top is a very popular choice and no one will be mad about it.
Should I rinse the potatoes?
No. For Dauphinoise, you generally do not rinse the sliced potatoes. That surface starch helps the cream thicken into a soft, clingy sauce instead of staying thin.
What potatoes work best?
Yukon Gold are the sweet spot: tender, creamy, and not watery. Russets work too and give a softer, more custardy result, but can drink up more cream.
Can I make this ahead?
Yes. Bake it, cool it, and refrigerate covered for up to 2 days. Reheat covered at 350°F until hot, then uncover for a few minutes to re-brown the top.
Why is my gratin watery?
Usually one of these: slices were too thick, the dish was underbaked, the cream was very cold when it went in, or the potatoes were rinsed. Slice thin, bake until truly tender, warm the cream before assembling, and skip the rinse.
