Brown-butter hash-brown gratin with chive sour cream

Refrigerate up to four days. Reheat uncovered at 400°F for 12–18 minutes. Store sour cream separately.

• Russet potatoes4 lb
• Unsalted butter0.25 cups
• Heavy cream1 cup
• Gruyère1 cup
• Sour cream1.5 cups
• Fresh chives0.25 cups
• Onion1 ea
• Parmesan0.5 cups

Multiplying the ingredients is the easy half. These are the parts of the recipe that the batch count does not move.

Cooking time

70 minutes in the oven, whatever fraction of the tray is filled. A half-full tray browns faster, so look at it sooner rather than trusting the clock.

1. Read the whole method before you shop. This is a planning recipe for brown-butter hash-brown gratin with chive sour cream, not a certified kitchen test.
2. Amounts below are one batch: 10 portions. Build a plan and this card scales itself to it.
3. This dish can be completed up to 1 day ahead. Cold storage is the real limit — do not make it ahead if the fridge is already tight.
4. Oven occupancy is 70 minutes per tray. Do not start this tray if the day-of oven window is already full.
5. Season, tray up, roast, rest. Hold only as long as the fixture hold time.
6. Holds about 30 minutes once finished. After that, quality drops — do not invent extra time.
7. Leftover route: Refrigerate up to four days. Reheat uncovered at 400°F for 12–18 minutes. Store sour cream separately.
8. Confirm every ingredient and every allergen yourself. Dietary tags are planning filters, not safety guarantees.