yam casserole

original recipe courtesy cook's illustrated, 2005

because natural sugar levels in yams vary greatly depending on variety, size, and season, it's important to taste the filling before adding sugar. if the filling is bland, add up to 4 tablespoons sugar; if the yams are naturally sweet, you may opt to omit the sugar altogether. when sweetening the filling, keep in mind that the streusel topping is quite sweet. for even cooking, buy yams that are uniform in size. avoid yams larger than 1 1/2 pounds; they require a longer roasting time and tend to cook unevenly. the yams can be baked up to 2 days ahead. scrape the flesh from the skins and refrigerate in an airtight container. to serve 4 to 6, halve all the ingredients and bake the casserole in an 8-inch-square baking dish for 35 to 40 minutes.

serves 4 to 6
3 1/2 pounds yams (3-4 medium)

streusel
2 1/2 tablespoons unsalted butter , cut into 3 pieces and softened, plus additional for greasing pan
1/4 cup all-purpose flour (1 3/4 ounces)
1/4 cup packed dark brown sugar (1 3/4 ounces)
1/8 teaspoon table salt
1/2 cup pecans (2 ounces)

filling
2 1/2 tablespoons unsalted butter , melted
1 teaspoons table salt
1/4 teaspoon ground nutmeg
1/4 teaspoon ground black pepper
1/2 tablespoon vanilla extract
2 teaspoons lemon juice (from 1/2 lemon)
granulated sugar
2 large egg yolks
3/4 cups half-and-half

a streusel topping with pecans is a more interesting option than the classic mini-marshmallows.


for the yams : adjust oven rack to lower-middle position and heat oven to 400 degrees. poke yams several times with paring knife and space evenly on rimmed baking sheet lined with aluminum foil. bake yams, turning them once, until they are very tender and can be squeezed easily with tongs, 1 to 1 1/2 hours (or 45 minutes for small yams). remove yams from oven and cut in half lengthwise to let steam escape; cool at least 10 minutes. reduce oven temperature to 375 degrees.

for the streusel: while yams are baking, butter 13 by 9-inch baking dish. pulse flour, brown sugar, and salt in food processor until blended, about four 1-second pulses. sprinkle butter pieces over flour mixture and pulse until crumbly mass forms, six to eight 1-second pulses. sprinkle nuts over mixture and pulse until combined but some large nut pieces remain, four to six 1-second pulses. transfer streusel to medium bowl and return empty workbowl to processor.

once potatoes have cooled slightly, use spoon to scoop flesh into large bowl. transfer half of yam flesh to food processor. using rubber spatula, break remaining yam flesh in bowl into coarse 1-inch chunks.

for the filling: add melted butter, salt, nutmeg, pepper, vanilla, and lemon juice to potatoes in food processor and process until smooth, about 20 seconds. taste for sweetness, then add up to 2 tablespoons granulated sugar, if necessary; add yolks. with processor running, pour half-and-half through feed tube and process until blended, about 20 seconds; transfer to bowl with potato pieces and stir gently until combined.

to assemble and bake casserole: pour filling into prepared baking dish and spread into even layer with spatula. sprinkle with streusel, breaking up any large pieces with fingers. bake until topping is well browned and filling is slightly puffy around edges, 40 to 45 minutes. cool at least 10 minutes before serving.

step by step: bye-bye moisture

instead of boiling sweet potatoes (as most recipes direct), roast them for a lighter, fluffier casserole.

as soon as sweet potatoes are finished cooking, cut them in half lengthwise so steam can escape.

step by step: are they done yet?

squeeze: although the outside might be tender, the center can still be firm. before removing sweet potatoes from the oven, squeeze them with a pair of tongs-they should give all the way to the center, without resistance.

peek: if you have doubts, cut sweet potatoes in half lengthwise. if you see whitish marbling (uncooked starches that are firm to the touch), press the halves back together, wrap the potatoes individually in foil, and continue roasting until the marbling disappears.