Here's a sweet potato casserole that will please everyone in the family, but isn't sticky or cloying. If your guests insist on a traditional marshmallow topping (let's admit that kids love it, and for some adults, it just isn't Thanksgiving without it), see the variation below.

　　

Ingredients

Makes 8 servings

　　5 pounds orange-fleshed sweet potatoes, such as Louisiana, jewel, or garnet yams

　　3/4 cup all-purpose flour

　　3/4 cup plus 1/3 cup (packed) light brown sugar

　　14 tablespoons (1 3/4 sticks) unsalted butter, softened

　　

Step 1

Position rack in center of oven and preheat to 400°F. Butter 9- by 13-inch baking dish or 2-quart casserole. Line rimmed baking sheet with aluminum foil.

　　

Step 2

Pierce each potato with fork and transfer to baking sheet. Bake until tender, about 50 minutes. Cool until easy to handle.

　　

Step 3

Meanwhile, make streusel: In medium bowl, combine flour, 3/4 cup brown sugar, and 1 stick butter. Rub mixture between fingertips until blended and crumbly. Set aside.

　　

Step 4

Halve potatoes lengthwise and scoop out flesh into large bowl. Add remaining 1/3 cup brown sugar and 3/4 stick butter and mash with potato masher or, for a smoother purée, handheld electric mixer. Spread mixture in prepared dish and cool completely. (Streusel and purée can be made up to 2 days ahead and refrigerated, separately, covered.)

　　

Step 5

Sprinkle streusel over potatoes. Bake until golden brown, about 40 minutes. Let stand 5 minutes before serving. (Completed dish can be prepared up to 1 day ahead and refrigerated, covered. Remove from refrigerator 1 hour before reheating and let come to room temperature. Bake, loosely covered with foil, until heated through, about 25 minutes.)

　　

Variation:

Step 6

Sweet potato purée with marshmallows: Omit streusel. Spread purée in baking dish, cover with foil, and bake until heated through, about 30 minutes. Sprinkle top with 3 cups miniature marshmallows and broil until marshmallows are lightly browned, about 1 minute. Serve immediately.

　　Test-Kitchen Tips:

　　•Most American cooks use the terms "sweet potato" and "yam" interchangeably, but there are actually three different types of vegetable referred to by these terms: The true sweet potato (also known as a boniato), available at Asian and Latino markets, has pale yellow flesh, skin with a purplish cast, and a chestnutlike flavor that isn't sweet at all. The true yam, also called a ñame (NYAH-meh), is a large tuber with scaly brown skin that's a staple of Caribbean, African, and Hispanic cuisines. The familiar, bright-orange-fleshed tubers called for in this recipe are a third type, a variety of the sweet potato that are often called "yams" to distinguish them from yellow-fleshed "true" sweet potatoes. The Louisiana, jewel, or garnet varieties will all work well.

　　•While some recipes for sweet potato purée call for boiling the potatoes, roasting gives a much sweeter, more concentrated flavor and drier texture.