Name: Poblano Potato Gratin
Cook time: 45 min
Total time: 2 1/2 hr
Yield: Makes 8 (side dish) servings
Ingredients: 1 1/2 pounds fresh poblano chiles (about 5); 1 pound onions, cut lengthwise into 1/4-inch strips; 1 tablespoon vegetable oil; 3 pounds large Yukon Gold potatoes; 1 1/2 cups heavy cream; 3/4 cup whole milk; Equipment: an adjustable-blade slicer

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Poblano Potato GratinDitte Isager

In Mexican cuisine, rajas refers to thin strips of roasted chiles. Although they commonly spice up everything from stews to tamales, rajas are best when adding a kick to creamy dishes. Here, forest-green poblanos lend a mild, almost fruity heat to a potato gratin.

Cooks notes:

•Chiles can be roasted by broiling on a broiler pan 2 inches from heat, turning, 8 to 10 minutes.
•Rajas can be made 3 days ahead and chilled.
•Gratin can be made 1 day ahead and chilled. Bring to room temperature and reheat, covered, in a 350°F oven (about 30 minutes).

Recipe information

Total Time
2 1/2 hr
Yield
Makes 8 (side dish) servings

Ingredients

1 1/2 pounds fresh poblano chiles (about 5)

1 pound onions, cut lengthwise into 1/4-inch strips

1 tablespoon vegetable oil

3 pounds large Yukon Gold potatoes

1 1/2 cups heavy cream

3/4 cup whole milk

Equipment: an adjustable-blade slicer

Preparation

Roast chiles and make rajas:
Step 1
Roast chiles on their sides on racks of gas burners on high, turning with tongs, until skins are blackened all over, about 10 minutes. Immediately transfer to a bowl and let stand, covered tightly, 10 minutes.
Step 2
When chiles are cool enough to handle, peel or rub off skin. Slit chiles lengthwise, then stem, seed, and devein. Cut lengthwise into thin strips.
Step 3
Cook onions with 1 teaspoon salt in oil in a 12-inch heavy skillet over medium-low heat, stirring occasionally, until golden, about 8 minutes. Stir in chiles and remove rajas from heat. Reserve 1/2 cup rajas for topping.
Make gratin:
Step 4
Preheat oven to 400°F with rack in middle. Generously butter a 3-quart shallow baking dish.
Step 5
Peel potatoes, then cut crosswise into 1/16-inch-thick slices with slicer. Transfer to a small heavy pot. Add cream, milk, and 1 teaspoon salt and bring just to a boil over medium heat, stirring occasionally (liquid will thicken). Stir in rajas, then pour mixture evenly into baking dish. Sprinkle reserved 1/2 cup rajas on top.
Step 6
Bake until potatoes are tender, 45 minutes to 1 hour. Let stand 15 minutes before serving.