Pimento-Cheese Potato Gratin

Set oven racks to middle and top position, and preheat oven to 375°F. Bring 2 quarts water and 2 teaspoons salt to a boil in a 3- to 4-quart pot. Add potatoes and cook for 10 minutes. Drain and set aside.

Combine cream, shallots, chile flakes, remaining 1 teaspoon salt, black pepper, and reserved liquid from jar of peppers in a small saucepan. Bring to a simmer and cook until chile flakes have begun to stain the cream, about 2 minutes.

Add half the cheese and stir until melted, about 1 minute. Remove from heat.

Layer a third of the potatoes in a 6-cup baking dish, overlapping if necessary. Scatter half the roasted peppers on top of potatoes (cut up any peppers that have remained whole so that they lie flat). Repeat until all peppers and potatoes have been used.

Pour cream mixture over potatoes and peppers; gently shake dish to distribute liquid. Cover with aluminum foil and bake on middle rack for 15 minutes. Uncover dish, sprinkle remaining cheese over top, and place dish on top oven rack. Bake until cheese is bubbly and lightly browned on top, about 8 minutes. Serve immediately.