This is America’s Test Kitchen Recipe from 2007, as part of their holiday makeover. It’s quite terrific. I know every family has their own version of this, but if you’re like me, you might also like to vary the marshmallow-topped yams every once in awhile. This recipe doesn’t disappoint!
Sweet Potato Casserole with Pecan Streusel
7 lbs. sweet potatoes, of similar size (6-8)
5 T. unsalted butter, cut into 5 pieces and softened, plus more for the pan
1/2 c. unbleached all-purpose flour
1/2 c. packed dark brown sugar
1/4 t. salt
1 c. pecans
5 T. unsalted butter, melted
2 t. salt
1/2 t. nutmeg
1/2 t. pepper
1 T. vanilla extract
4 t. fresh lemon juice
4 large egg yolks
1 1/2 c. half-and-half
1. For the sweet potatoes: Adjust an oven rack to lower-middle position and heat oven to 400. Poke the potatoes with a fork or knife and place on a rimmed baking sheet lined with aluminum foil. Bake until they are very tender (they easily pierce or can be squeezed with tongs), 1-1 1/2 hours. Remove from oven and cut in half lengthwise, and let cool ten minutes. Turn the oven down to 375.
2. For the streusel: while the potatoes are baking, butter a 13 x 9 inch dish. Pulse the flour, brown sugar, and salt in a food processor until blended, 4 times. Sprinkle the butter over the top and pulse, 6-8 times. Then, add the nuts and pulse, 4-6 times. (If you don’t have a food processor, you can mix the first three ingredients with your fingers or a fork, and the butter, and mix again with your fingers until big crumbs form. Then, chop the nuts–to however small you prefer–on a separate surface, and add and combine. It should look like streusel.)
Once the potatoes have cooled, scoop out the flesh into a large bowl. Transfer half the flesh to the food processor; cut the remaining flesh into coarse 1-inch chunks.
3. For the filling: add the melted butter, salt, nutmeg, pepper, vanilla, and lemon juice to the potatoes in the food processor and process until smooth, about 20 seconds. Taste for sweetness, then add up to 4 T. granulated sugar, if necessary; add the yolks. With the processor running, pour the half-and-half through the feed tube and process until blended, about 20 seconds. Transfer to the bowl with the potato pieces and stir gently to combine. (Alternately, blend or mash half the sweet potato flesh well, then add the ingredients as listed above, using a wooden spoon to combine. I don’t have a food processor, and these still turned out really well.)
4. Assemble and Bake: Pour the filling into the prepared baking dish and spread into an even layer with the spatula. Sprinkle with the streusel, breaking up any large pieces with your fingers. Bake until the topping is well browned and the filling is slightly puffy around the edges, 40-45 minutes. Cool at least 10 minutes before serving.
Note: to cut down on Thanksgiving-day work, you can bake the sweet potatoes up to two days in advance, scrape the flesh out, and store in an airtight container in the fridge. Then, proceed from step 2.