Purple Sweet Potato Casserole

READY IN: 45mins




  • Place sweet potatoes in a large saucepan and cover with cold water by 2 inches.  Salt generously.  Bring to a boil, then reduce heat to a simmer and cook until sweet potatoes are easily pierced with the tip of a paring knife, 15-20 minutes.
  • Meanwhile, combine egg whites, sugar, and salt in the heatproof bowl of a stand mixer set over a pan of simmering water.  Whisk constantly by hand until mixture is warm to the touch and sugar has dissolved (the mixture should feel completely smooth when rubbed between your fingertips).
  • Attach the bowl to a mixer fitted with the whisk attachment.  Starting on low and gradually increasing to medium-high speed, whisk until stiff, but not dry, peaks form.  Continue mixing until meringue is fluffy and glossy and completely cool (test by touching the bottom of the bowl), 10-15 minutes.  Add vanilla and pumpkin pie spice and mix on low just until combined.  Transfer meringue to a disposable piping bag fitted with a 1A Wilton decorating tip and set aside.
  • When sweet potatoes have finished cooking, drain, then return to pan.  Heat over medium, stirring, until any remaining liquid has evaporated and a thin film covers bottom of pan, about 2 minutes.
  • Remove pan from heat.  Add milk and butter and mash until smooth.  Season to taste with salt and pepper.  Transfer mashed sweet potatoes to a buttered 8x8” square baking dish.  Using the meringue, pipe a checkerboard pattern onto the potatoes.  Toast meringue with a kitchen torch, or place under a broiler, until peaks are toasted and golden and serve.