Ingredients:

  • 2 medium sweet potatoes (about 1 lb / 450g), scrubbed
  • 1 tbsp olive oil (15ml)
  • 1/4 tsp salt (1.5g)
  • 1/4 tsp black pepper (1.5g)
  • 6 tbsp unsalted butter (85g)
  • 1/4 cup all-purpose flour (30g)
  • 1 cup whole milk (240ml)
  • 1/4 cup maple syrup (60ml)
  • 1/4 tsp ground nutmeg (0.5g)
  • 1/4 tsp salt (1.5g)
  • 3 large egg yolks (60g)
  • 1 tbsp fresh sage, finely chopped (4g)
  • 4 large egg whites (120g), room temperature
  • 1/4 tsp cream of tartar (1g)
  • 2 tbsp granulated sugar (25g)
  • 2 tbsp unsalted butter, softened, for greasing
  • 2 tbsp granulated sugar, for dusting

Instructions:

  1. Preheat oven to 400°F (200°C). Toss sweet potatoes with olive oil, salt, and pepper. Roast until very tender, about 45-60 minutes. Let cool slightly, then scoop out the flesh and mash until smooth. Measure out 1 1/2 cups (340g).
  2. In a medium saucepan over medium heat, melt the butter. Cook, swirling occasionally, until it turns a nutty brown color and has a fragrant aroma (about 5-7 minutes). Immediately remove from heat and set aside to cool slightly.
  3. In the same saucepan, whisk together the flour and milk over medium heat until smooth. Cook, whisking constantly, until the mixture thickens into a béchamel.
  4. Stir in the maple syrup, nutmeg, and salt. Remove from heat and whisk in the egg yolks one at a time, ensuring each is fully incorporated before adding the next. Stir in the browned butter (including the browned milk solids) and sage.
  5. Gently fold the sweet potato puree into the bechamel mixture until just combined.
  6. Preheat oven to 375°F (190°C). Generously butter the inside of each ramekin, then coat with sugar, tapping out any excess.
  7. In a large, clean bowl, beat the egg whites with cream of tartar until soft peaks form. Gradually add the sugar, beating until stiff, glossy peaks form. Don't overbeat!
  8. Gently fold one-third of the meringue into the sweet potato mixture to lighten it. Then, gently fold in the remaining meringue in two additions, being careful not to deflate the mixture.
  9. Divide the souffle mixture evenly among the prepared ramekins, filling them almost to the top. Smooth the tops.
  10. Bake for 35-40 minutes, or until the souffles are puffed up and golden brown. Open the oven carefully!
  11. Serve immediately, as souffles will deflate as they cool.