The Cook's Illustrated Cookbook (134 page)
Read The Cook's Illustrated Cookbook Online
Authors: The Editors at America's Test Kitchen
Tags: #Cooking
WHY THIS RECIPE WORKS
Too often, roasted sweet potatoes turn out starchy and wan. We wanted a method that gave us potatoes with a nicely caramelized exterior, a smooth, creamy interior, and an earthy sweetness. Cutting them into ³⁄
4
-inch-thick rounds and laying them flat on a baking sheet ensured even cooking. A few experiments proved a lower roasting temperature resulted in a sweeter potato, so we started the sliced potatoes in a cold (versus preheated) oven and covered them with aluminum foil, which allowed plenty of time for their starches to convert to sugars. We removed the foil after 30 minutes and continued to roast the potatoes until crisp.
SERVES 4 TO 6
Note that this recipe calls for starting the potatoes in a cold oven. Choose potatoes that are as even in width as possible; trimming the small ends prevents them from burning. If you prefer not to peel the potatoes, just scrub them well before cutting.
3 | pounds sweet potatoes, ends trimmed, peeled, rinsed, and cut into ³⁄ |
2 | tablespoons vegetable oil |
1 | teaspoon salt |
Pepper |
1.
Toss potatoes in large bowl with oil, salt, and pepper to taste until evenly coated. Line rimmed baking sheet with aluminum foil and coat with vegetable oil spray. Arrange potatoes in single layer on baking sheet and cover tightly with foil. Adjust oven rack to middle position and place potatoes in cold oven. Turn oven to 425 degrees and bake potatoes for 30 minutes.
2.
Remove baking sheet from oven and carefully remove top piece of foil. Return potatoes to oven and cook, uncovered, until bottom edges of potatoes are golden brown, 15 to 25 minutes.
3.
Remove baking sheet from oven and, using thin metal spatula, flip potato slices over. Continue to roast until bottom edges of potatoes are golden brown, 18 to 22 minutes longer. Remove from oven, cool for 5 to 10 minutes, and serve.
Whisk ¹⁄
4
cup maple syrup, 2 tablespoons melted unsalted butter, and 2 teaspoons minced fresh thyme together in small bowl. Follow recipe as directed through step 2. After removing baking sheet from oven in step 3, brush potatoes with half of maple syrup glaze, flip slices over with thin metal spatula, and brush with remaining glaze. Return potatoes to oven and proceed as directed.
Heat ¹⁄
4
cup packed light brown sugar, 2 tablespoons apple juice, 2 tablespoons unsalted butter, ¹⁄
4
teaspoon ground cinnamon, ¹⁄
4
teaspoon ground ginger, and ¹⁄
8
teaspoon ground nutmeg in small saucepan over medium heat. Cook, stirring constantly, until butter has melted and sugar is dissolved, 2 to 4 minutes. Follow recipe as directed through step 2. After removing baking sheet from oven in step 3, brush potatoes with half of spice glaze, flip slices over with thin metal spatula, and brush with remaining glaze. Return potatoes to oven and proceed as directed.
WHY THIS RECIPE WORKS
We wanted a method for making mashed sweet potatoes that would push their deep, earthy sweetness to the fore and produce a silky puree with enough body to hold its shape on a fork. We braised sliced sweet potatoes in a mixture of butter and heavy cream to impart a smooth richness. Adding salt brought out the potatoes’ delicate flavor, and just a teaspoon of sugar bolstered their sweetness. Once the potatoes were tender, we mashed them in the saucepan with a potato masher. We skipped the typical pumpkin pie seasoning and instead let the simple sweet potato flavor shine through.
SERVES 4
Cutting the sweet potatoes into slices of even thickness is important in getting them to cook at the same rate. A potato masher will yield slightly lumpy sweet potatoes; a food mill will make a perfectly smooth puree.
2 | pounds sweet potatoes, peeled, quartered lengthwise, and cut crosswise into ¹⁄ |
4 | tablespoons unsalted butter, cut into 4 pieces |
2 | tablespoons heavy cream |
1 | teaspoon sugar |
¹⁄ | teaspoon salt |
Pinch pepper |
1.
Combine sweet potatoes, butter, cream, sugar, and salt in large saucepan and cook, covered, over low heat, stirring occasionally, until potatoes fall apart when poked with fork, 35 to 45 minutes.
2.
Off heat, mash sweet potatoes in saucepan with potato masher (Alternatively, you can you use ricer or food mill to press or mill potatoes into warmed serving bowl.) Stir in pepper; serve immediately.
Stir in 2 tablespoons maple syrup and ¹⁄
2
teaspoon grated orange zest along with pepper just before serving.
Substitute dark brown sugar for granulated sugar and add ³⁄
4
teaspoon garam masala to saucepan along with sweet potatoes in step 1. Stir ¹⁄
4
cup golden raisins and ¹⁄
4
cup roasted unsalted cashews, chopped coarse, into mashed sweet potatoes along with pepper just before serving.
Substitute ¹⁄
2
cup coconut milk for butter and cream and add ¹⁄
4
teaspoon red pepper flakes and 1 small minced garlic clove to saucepan along with sweet potatoes in step 1. Stir in 1 tablespoon minced fresh cilantro along with pepper just before serving.
WHY THIS RECIPE WORKS
More dessert than side dish, the typical version of this holiday favorite swamps this casserole in sugar, fat, and spices. We wanted to bring the sweet potatoes to the forefront. We rejected a number of topping options we found in other versions—nuts, canned pineapple, maraschino cherries, corn flakes, Rice Krispies, bread crumbs—and settled on a streusel made with dark brown sugar and slightly bitter pecans, which kept the sweetness to a minimum while adding texture. And we cut back on the traditionally excessive amounts of sugar and cream in the filling and boosted the sweet potato flavor by roasting the potatoes. A food processor created a silky smooth base, to which we added some reserved potato chunks for textural interest. We were stingy with the spices; nutmeg, black pepper, vanilla, and a splash of lemon juice added brightness without making the casserole taste like pie.
SERVES 10 TO 12
Because natural sugar levels in sweet potatoes 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 potatoes 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. If you can find them, Beauregard, Garnet, or Jewel sweet potatoes have the best texture for this recipe. For even cooking, buy potatoes that are uniform in size. Avoid potatoes larger than 1¹⁄
2
pounds; they require a longer roasting time and tend to cook unevenly. The potatoes 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.
POTATOES
7 | pounds sweet potatoes |
STREUSEL
5 | tablespoons unsalted butter, cut into 5 pieces and softened, plus extra for pan |
¹⁄ | cup (2¹⁄ |
¹⁄ | cup packed (3¹⁄ |
¹⁄ | teaspoon salt |
1 | cup pecans |
FILLING
5 | tablespoons unsalted butter, melted |
1 | tablespoon vanilla extract |
4 | teaspoons lemon juice |
2 | teaspoons salt |
¹⁄ | teaspoon ground nutmeg |
¹⁄ | teaspoon pepper |
Granulated sugar | |
4 | large egg yolks |
1¹⁄ | cups half-and-half |
1. FOR THE POTATOES:
Adjust oven rack to lower-middle position and heat oven to 400 degrees. Poke sweet potatoes several times with paring knife and space evenly on aluminum foil–lined rimmed baking sheet. Bake potatoes, turning once, until they are very tender and can be squeezed easily with tongs, 1 to 1¹⁄
2
hours (or 45 minutes for small sweet potatoes). Remove potatoes from oven and cut in half lengthwise to let steam escape; cool at least 10 minutes. Reduce oven temperature to 375 degrees.
2. FOR THE STREUSEL:
While potatoes are baking, butter 13 by 9-inch baking dish. Pulse flour, brown sugar, and salt in food processor until blended, about 4 pulses. Sprinkle butter pieces over flour mixture and pulse until crumbly mass forms, 6 to 8 pulses. Sprinkle nuts over mixture and pulse until combined but some large nut pieces remain, 4 to 6 pulses. Transfer streusel to medium bowl and return now-empty workbowl to processor.
3.
Once potatoes have cooled slightly, use soupspoon to scoop flesh into large bowl (you should have about 8 cups). Transfer half of potato flesh to food processor. Using rubber spatula, break remaining potato flesh in bowl into coarse 1-inch chunks.
4. FOR THE FILLING:
Add melted butter, vanilla, lemon juice, salt, nutmeg, and pepper to potatoes in food processor and process until smooth, about 20 seconds. Taste for sweetness, then add up to 4 tablespoons granulated sugar, if necessary. Add egg yolks. With processor running, pour in half-and-half and process until blended, about 20 seconds. Transfer mixture to bowl with potato pieces and stir gently until combined.
5. 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.