Sweet Potato Crumble Crisp
A silky custard sweet potato base under a buttery brown sugar oat crumble that bakes up genuinely crisp. Two bowls, one dish, one bake.
Servings 10 servings
Ingredients
For the Filling
- 2 cups mashed sweet potato about 2 large, roasted not boiled
- 3 large eggs room temperature
- ⅔ cup heavy cream
- ½ cup brown sugar packed
- 2 teaspoons pumpkin pie spice
- 2 teaspoons vanilla extract
- ½ teaspoon salt
For the Crumble Topping
- 1 ½ cups all-purpose flour
- ⅔ cup quick oats or old-fashioned rolled oats
- ⅔ cup brown sugar packed
- 2 teaspoons ground cinnamon
- 12 tablespoons unsalted butter cold and cubed
- ⅓ cup chopped pecans optional, toasted
Instructions
Roast and Mash the Sweet Potatoes
- Prick the sweet potatoes all over with a fork and roast whole at 400 degrees F for 45 to 55 minutes, until a knife slides in with no resistance.
- Cool until you can handle them, scoop the flesh from the skins, and mash until smooth. Measure out 2 cups.
Make the Custard Base
- Reduce the oven to 350 degrees F and butter a 9x13-inch baking dish.
- Whisk the mashed sweet potato with the eggs, heavy cream, brown sugar, pumpkin pie spice, vanilla, and salt until completely smooth. Stop as soon as it is uniform to avoid whipping in air.
- Spread the filling into the prepared dish in an even layer.
Cut the Crumble and Bake
- In a second bowl, whisk together the flour, quick oats, brown sugar, and cinnamon.
- Cut in the cold cubed butter with a pastry cutter or two forks until the mixture forms loose clumps ranging from small peas to coarse gravel. Fold in the pecans if using.
- Scatter the crumble evenly over the filling all the way to the edges. Do not press it down.
- Bake uncovered for 45 to 55 minutes, until the topping is deep golden and the filling jiggles as one unit with no liquid ripple at the center.
- Rest 20 minutes before serving so the custard finishes setting. Serve warm with vanilla ice cream.
Notes
- Roast, never boil: Boiled sweet potatoes carry extra water into the custard and warmth the topping soft from below.
- Cold butter only: Cut cold cubed butter into the dry mix. Melted butter makes a paste that bakes dense and sandy.
- Bake uncovered: No foil at any point. A cover traps warmth and ruins the crumble.
- Watery mash rescue: Spread the mash on a sheet pan and dry it at 300 degrees F for 10 minutes before mixing.
- Canned sweet potatoes: Drain well, reduce cream to ⅓ cup, and if packed in syrup cut the filling brown sugar to ⅓ cup.
- Storage: Cool uncovered, then cover and refrigerate up to 4 days. Reheat uncovered at 350 degrees F for 15 to 20 minutes.
- Fruit crisp variation: Layer 2 cups diced apple and ½ cup cranberries over the custard before topping, and add 8 minutes to the bake.