Sweet Potato Soufflé

Preparation

1. Step 1

   Bring a large pot of water to a boil. Meanwhile, peel and cut sweet potatoes into 1-inch cubes. 

2. Step 2

   Add the potatoes to the boiling water and cook, uncovered, stirring occasionally, until very tender when pierced with a fork, about 20 minutes.

3. Step 3

   While the potatoes are cooking, heat oven to 350 degrees. Butter a 2 ½- to 3-quart baking dish.

4. Step 4

   Drain the cooked potatoes well. Let cool slightly then transfer to a large bowl and mash. Measure out 5 ¾ cups/3 ½ pounds mashed sweet potatoes (reserving any extra for another use) and place back in the large bowl. 

5. Step 5

   Using an electric mixer, beat the potatoes on low speed until smooth. With the mixer still on low speed, beat in the melted butter. Add egg yolks and beat until well blended. Add sugar, cream, lemon zest, ginger and salt, and beat to combine. 

6. Step 6

   In another large clean bowl, whisk the egg whites on medium-low until stiff peaks form. Working in three batches, add the whipped egg whites to the sweet potato mixture and fold by scraping around the sides of the bowl and then through the middle, rotating the bowl until evenly incorporated.

7. Step 7

   Carefully transfer the mixture to the prepared baking dish and gently smooth the top. 

8. Step 8

   Bake until browned in spots, slightly puffed all over and set in the middle when lightly touched, 1 hour to 1 hour 10 minutes. Serve immediately.