Why It Works
- Simmering tenderizes the sweet potatoes, condenses the dairy, and extracts a deeper aroma of cinnamon, nutmeg, and vanilla.
- DIY "condensed" milk has a lighter, fresher flavor than canned, with a subtle toffee taste.
- Plain white sugar balances the pH of the dairy, which would instantly curdle if boiled with brown sugar.
- A digital thermometer eliminates guesswork; the pie is done when it reaches an internal temperature of 195°F.
Having grown up down South, I can't imagine Thanksgiving or Christmas without a sweet potato pie. If that's not a familiar tradition for you, I can understand the temptation to see it as a mere replacement for pumpkin. But resist that urge, and trust me when I say that sweet potato pie is a thing unto itself.
Here's the deal. Pumpkin doesn't have much in the way of flavor, so it needs to be spiced seven ways to Sunday to taste like anything at all, and perhaps that's why "pumpkin spice" blends don't even bother to include the eponymous ingredient. Cooked pumpkin is also watery and bland, so, whether your purée is homemade or store-bought, it perks up only with the addition of lots of sugar and fat, giving the pie a dense, custardy texture.
But sweet potatoes? Once roasted, sweet potatoes are so deliciously rich, creamy, and flavorful, they can be served with nothing more than a pinch of salt. That simplicity is reflected in traditional recipes, which involve little else beyond milk, eggs, cinnamon, and nutmeg. Brown sugar is a purely modern twist: Nineteenth-century recipes called for plain sugar if they called for any at all, but the sweet potatoes most often spoke for themselves.
That idea runs contrary to the perspective of today's food world, which is obsessed with layering ingredients to add complexity and depth, but when one ingredient is piled on top of the next in endless succession, you don't always build flavor. Sometimes you bury it. In the case of sweet potato pie, there's something to be said for simplicity—letting a few thoughtfully chosen ingredients work together in concert, without any stray chords to distract from their harmony.
When made with ginger, cloves, brown sugar, and an excess of fat, sweet potato pie tastes like a knockoff version of pumpkin, equally heavy and dark. But when made according to those bare-bones 19th-century recipes, sweet potato pie comes together in one perfect note, bright and clean. That very lightness makes it the perfect match for a big meal, when our palates have been overwhelmed by a multitude of dishes and our pants are a little snug.
Of course, my appreciation for time-honored recipes doesn't mean I take a strictly old-fashioned approach. In accordance with recipes from the 1800s, I boil my sweet potatoes until they're tender and sweet, but instead of water, I use a blend of milk and cream.
Now, prolonged boiling would normally cause milk to curdle, as its acidity is concentrated over time. But, as with my homemade cajeta, curdling can be avoided with the addition of alkaline ingredients. With cajeta, that's a spoonful of baking soda, but for sweet potato pie, I reach for a slightly alkaline spice: cinnamon.
Not only does this method infuse sweet potatoes with flavor from the inside out, it also cooks off more than a pound of water, essentially condensing the milk. In turn, that coaxes out the mellow toffee notes we associate with canned milk, but not to the same degree, keeping the custard's flavor comparatively fresh.
An immersion blender transforms the chunky mixture into a silky purée, and the custard itself can be made straight in the pan. Just whisk in the remaining ingredients, and you're done.
The thick custard can be held for a week in the fridge, then brought to room temperature—or it can be poured straight into a fully baked pie crust, because it won't be in the oven long enough for the crust to crisp up on its own. Follow my blind-baking tutorial, and you'll be good to go.
The pie bakes for just 45 minutes at 350°F (177°C), or until the custard is gently set—about 195°F (91°C) in the very center. This temperature is a bit higher than what you see recommended for most custard pies, but that's due to its unusually low moisture content. That fact makes the custard especially silky, while ensuring the crust itself stays flaky and crisp, particularly if you're using my Old-Fashioned Flaky Pie Dough (whose relatively high moisture content makes it disinclined to absorb other liquids).
Those unique factors mean that my sweet potato pie can be held overnight at room temperature without any detriment to the crust, so it's a great make-ahead recipe for the holidays.
Also make-ahead? My brown sugar whipped cream, which stays fluffy and light even after a few days in the fridge. Diluted in cream, brown sugar provides just a hint of butterscotch to complement, rather than compete with, the sweet potatoes. Or, if you'd prefer to match the understated simplicity of the pie, a dollop of plain whipped cream would be swell.
Regardless of how it's served, I hope this sweet potato pie finds its way to your Thanksgiving table. Whether you're craving a change of pace, or just a change of technique, its sweet simplicity is a beautiful conclusion to any meal.
16 ounces sweet potatoes (3 1/3 cups; 455g) from 2 medium sweet potatoes, peeled, roughly diced (see note)
1 vanilla bean, split and scraped, seeds reserved for whipped cream topping
2 or 3 cinnamon sticks (about 6 inches total)
1 whole nutmeg (see note)
26 ounces milk (3 1/4 cups; 740g), any percentage will do
6 ounces heavy cream (3/4 cup; 170g)
7 ounces white or lightly toasted sugar (1 cup; 195g)
1 tablespoon ground cinnamon
1 teaspoon freshly grated nutmeg
1/2 teaspoon Diamond Crystal kosher salt; use half as much if iodized table salt
1/2 ounce vanilla extract (1 tablespoon; 14g)
3 large eggs
Brown sugar whipped cream (optional)
In a 3-quart stainless steel saucier, combine sweet potatoes, empty vanilla pod, cinnamon sticks, whole nutmeg, milk, cream, and sugar. If you have a scale, write down the weight of the saucier and combined ingredients so you can precisely measure the reduction.
Bring to a boil over high heat, then adjust to medium-low and maintain a gentle simmer (higher heat may cause the milk to curdle). Scrape frequently with a flexible spatula to prevent milk solids from building up around the side, and simmer until sweet potatoes are fall-apart tender and dairy has condensed into a thick sauce, about 55 minutes. The saucier should weigh 19 ounces (535g) less than when you started. (Alternatively, total volume, including cooked sweet potato, should be 3 2/3 cups when finished.)
Adjust oven rack to lower-middle position and preheat to 350°F (177°C). Remove vanilla bean and spices from saucier and purée sweet potato and dairy mixture with an immersion blender until smooth. (If needed, transfer to a smaller container to avoid splashing.) Whisk in ground cinnamon, grated nutmeg, salt, and vanilla, followed by eggs. If you like, strain through a fine-mesh strainer before pouring into prepared pie crust.
Bake pie until gently set in the middle with an internal temperature of 195°F (91°C), about 40 minutes. Cool at least 20 minutes before slicing with a chef's knife, pausing to wipe the blade clean as needed. If desired, serve with dollops of brown sugar whipped cream. Wrapped in plastic, sweet potato pie will keep for up to 3 days at cool room temperature.
I love the bright color of garnet yams in this recipe—don't worry, despite the name, they're actually sweet potatoes—but any true sweet potato will do. This recipe will not work with butternut squash or pumpkin, both of which develop an unpalatable vegetal quality with boiling.
Even if you're not a big fan of nutmeg, you'll be surprised at how well it pairs with the sweet potato custard, coaxing out a sense of brightness and cutting through the dairy fat. In the quantities used here, it has a fresh, almost herbaceous flavor, owing to its high levels of myristicin, an essential oil common to parsley and dill.
|Nutrition Facts (per serving)|
|Amount per serving|
|% Daily Value*|
|Total Fat 15g||19%|
|Saturated Fat 7g||35%|
|Total Carbohydrate 43g||16%|
|Dietary Fiber 3g||9%|
|Total Sugars 24g|
|Vitamin C 8mg||38%|
|*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.|