Clean and cook the sweet potatoes until flesh is tender. Either prick and bake or microwave. About 40 minutes if baking, about 5-7 minutes if microwaving, depending on the size and number of sweet potatoes.
Peel and reserve flesh. (I save the peels for my dog)
In the bowl of a mixer, fitted with a paddle, beat the sweet potatoes for 1 or 2 minutes, until almost smooth.
In a saucepan over a medium heat, melt butter and sage together, watching carefully until it begins to turn golden brown. Just as it turns nutty brown and fragrant, remove from the heat and add to the mashed sweet potato.
Blend sweet potato mash and browned butter and sage until mixed. Season with salt and pepper to taste.
Serves 6, 1/2 cup each.