Line a baking sheet with foil and preheat your oven to 425F. Move the rack to the middle position. Place whole, unpeeled sweet potatoes on the baking sheet. Carefully prick potatoes all over with a knife. Bake for 45-50 minutes or until very soft.
Meanwhile, when the sweet potatoes are about ready, add the butter, cream, sage, rosemary, cinnamon, and salt & pepper to a small saucepan and warm over a low heat for 10 minutes, stirring every so often.
Cut the sweet potatoes in half lengthwise (to let the steam escape), and let them cool for a few minutes until they're cool enough to handle. Scoop out the flesh and add it to a pot.
Pour the warm cream mixture into the pot and mash the sweet potatoes with a hand-held potato masher until smooth.
Transfer them to a bowl and serve immediately. For the garnish in the photos (optional), I added about a teaspoon of cream + a couple tablespoons of butter and microwaved it until melted. I then poured it over the mashed sweet potatoes.
Notes
Sweet potatoes vary so much in size, so that's why I suggest a weight. I had 5 small-medium sweet potatoes in the 3 pounds for this recipe.
If you prefer, you can boil the sweet potatoes instead of baking. To do this, peel the sweet potatoes and cut them into 1" (or so) pieces. Add them to a pot, cover with water, and boil until tender.
Nutritional information is provided as a courtesy only and should be construed as an estimate rather than a guarantee. Ingredients can vary and Salt & Lavender makes no guarantees to the accuracy of this information.