This silky puréed soup is so cozy on a winter’s evening. A splash of vinegar balances the sweetness of the root veggies.
1. Thinly slice the shallots and carrots. Peel and chop the sweet potatoes.
2. In a small skillet, heat the oil and butter on medium until butter melts. Add shallots and thyme. Cook 4 min., until shallots are golden, stirring often. Transfer to a slow cooker bowl. Add sweet potatoes, carrots, and water. Season with salt. Cover and cook on low 3–4 hours, until sweet potatoes are very tender.
3. In a blender in batches or with immersion blender, purée soup until smooth. Stir in the vinegar. Season with salt and pepper to taste. Garnish with the parsley.
Garnish with croutons and a dollop of plain yogurt.