4 lb sweet potatoes, scrubbed well
1 head garlic, cloves separated and unpeeled
1/2 cup low-sodium chicken or vegetable broth
1 1/2 tbsp fresh rosemary leaves, chopped
1/2 tsp sea salt
Fresh ground black pepper, to taste
4 large egg whites (TIP: Be sure to use fresh egg whites for optimal lift.)
1/2 tsp cream of tartar
Preheat oven to 400?F.
Using a fork, prick each potato 2 to 3 times. Place potatoes on a baking sheet, transfer to oven and bake for 45 minutes to 1 hour or until softened.
Meanwhile, loosely wrap garlic in foil, sealing tightly. Place on a separate baking sheet, transfer to oven and bake for 30 to 35 minutes, until softened but not browned.
Remove potatoes and garlic from oven and let cool. When cool enough to handle, peel potatoes and place in a large bowl. Squeeze garlic cloves from their skins and add to bowl. Add broth and use a potato masher to mash until smooth; stir in rosemary, salt and pepper.
In a separate large bowl, combine egg whites and cream of tartar. Using an electric mixer, beat on high speed until stiff peaks form, 2 to 3 minutes. With a rubber spatula, gently fold half of egg white mixture into potato mixture until just a few white streaks are visible. Fold in remaining egg white mixture, allowing a few small white streaks to remain visible.
Coat a 9 x 13-inch baking dish with cooking spray. Add potato mixture, using spatula to smooth top. Transfer to oven and bake for 30 to 35 minutes, until top is lightly browned. Serve hot.
recipe from: https://www.cleaneatingmag.com