From Teresita 'Omey' Olson
Ingredients
 Butter4 tbsp
unsalted
 Shallot1 whole
 Thyme4 sprigs
 Water4 1/2 cups
alternative is low-sodium broth
 Sweet potato2 lbs
 Sweet potato peel
1/4 of the 2 lbs
 Brown sugar1 tbsp
alternative is maple syrup
 Cider vinegar 1/2 tsp
  Salt
  Pepper
1
Melt butter or heat oil in a large saucepan over medium-low heat. For vegans, substitute butter with coconut oil or avocado oil.
2
Add thinly sliced shallot and thyme to saucepan and cook until shallot softened but not browned (about 5 minutes).
3
Add water, increase heat to high and bring to a simmer.
4
Peel sweet potatoes, halve them lengthswise and slice to 1/4 inch thick pieces.
5
Remove pot from heat and add sweet potatoes and reserved peels. Let it stand uncovered for 20 minutes.
6
Add sugar, vinegar, 1-1/2 teaspoons of salt, ¼ teaspoon of pepper. Bring to a simmer over high heat.
7
Reduce heat to medium low, cover and cook until potatoes are very soft and tender (about 10 minutes).
8
Discard thyme sprigs.
9
Working in small batches, process soup in blender until smooth and creamy (about 30-60 seconds depending on blender).
10
Season with salt and pepper and serve immediately.
Notes

Serves 4-6 as a main dish or 8 as a starter.