Citrus-Marinated Gratin Dauphinois with Charred Onion

Method

A few unhurried steps. Read them through once before you start.

1. Gather and prep everything first: measure the spices, chop the aromatics, and bring the main ingredients to room temperature so they cook evenly.
2. Warm a generous glug of olive oil in a wide skillet over medium-high heat until it shimmers.
3. Add the main ingredients and cook, stirring now and then, until browned and just cooked through. Season in layers as you go.
4. Build the sauce and finish with Charred Onion: stir through the fresh herbs, adjust salt and acid, and let everything come together off the heat for a minute or two.
5. Serve the gratin dauphinois warm, with plenty of good bread or a simple salad alongside. This makes about 8 servings; leftovers keep well for a day.