Ingredients:

  • 4 large sweet potatoes (approx. 4 lbs / 1.8 kg), peeled and cubed
  • 1/2 cup (115 g) unsalted butter, divided
  • 1/4 cup (50 g) light brown sugar, packed
  • 2 large eggs, room temperature, lightly whisked
  • 1/4 cup (60 ml) whole milk or heavy cream
  • 1 teaspoon vanilla extract
  • 1 teaspoon ground cinnamon (for filling)
  • 1/4 teaspoon ground nutmeg
  • 1/2 teaspoon fine sea salt (for filling)
  • 1/2 cup (65 g) all-purpose flour (for streusel)
  • 1/2 cup (100 g) dark brown sugar, packed (for streusel)
  • 1/2 teaspoon ground cinnamon (for streusel)
  • Pinch fine sea salt (for streusel)
  • 1/4 cup (57 g) cold unsalted butter, diced (for streusel)
  • 1 cup (100 g) chopped pecans, lightly toasted
  • 1 tablespoon neutral oil (for roasting)
  • 1 cup (50 g) mini marshmallows (optional)

Instructions:

  1. Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper.
  2. Toss the peeled and cubed sweet potatoes lightly with 1 tablespoon of neutral oil and a pinch of salt. Spread them on the prepared baking sheet. Roast for 35–40 minutes, or until fork-tender and slightly caramelized around the edges.
  3. Remove potatoes from the oven and allow them to cool slightly (about 10 minutes). Reduce oven temperature to 350°F (175°C).
  4. Brown the Butter: Melt the 1/2 cup (115g) butter in a saucepan over medium heat. Continue cooking, swirling occasionally, until the milk solids turn a deep amber color and smell nutty. Immediately pour the brown butter into a heat-safe bowl, leaving any black sediment behind. Let cool slightly.
  5. Transfer the roasted sweet potatoes to a large mixing bowl. Mash thoroughly until smooth. For the smoothest result, use an electric hand mixer or immersion blender.
  6. Combine Wet Ingredients: Whisk the light brown sugar, salt, cinnamon, nutmeg, and vanilla into the cooled brown butter.
  7. Emulsify: Add the eggs one at a time, whisking well after each addition. Stir in the whole milk or heavy cream.
  8. Mix Filling: Pour the wet ingredients into the mashed potatoes. Mix well until the filling is homogenous, creamy, and smooth. Scrape the filling into the prepared 9x13 inch baking dish, smoothing the top.
  9. Make the Streusel: In a medium bowl, whisk together the flour, dark brown sugar, cinnamon (for streusel), and a pinch of salt. Add the diced cold butter and use your fingertips or a pastry blender to cut the butter into the dry ingredients until the mixture resembles coarse crumbs.
  10. Add Pecans: Stir in the chopped pecans. Sprinkle the streusel evenly over the sweet potato filling.
  11. Initial Bake: Bake at 350°F (175°C) for 25–30 minutes, or until the filling is set and the streusel is golden brown.
  12. Optional Finish: If using marshmallows, remove the casserole and sprinkle them over the top. Return to the oven for 3-5 minutes, or place under a low broiler for 60-90 seconds, watching very closely until the marshmallows are toasted.
  13. Rest: Allow the Sweet Potato Casserole to rest for 10 minutes before serving.