Melt 1 1/2 Tbsp. Pure Blends™ Avocado Oil Plant-Based Butter in Dutch oven or other large pot and cook shallots over medium heat, stirring occasionally, until golden, about 8 minutes. Remove and set aside.
Melt 4 Tbsp. Plant-Based Butter in same pot over medium heat and cook cauliflower, potatoes, onion, carrots, celery and garlic, stirring occasionally, until they begin to soften, about 5 minutes.
Stir in vegetable stock, water, 1/2 tsp. thyme and salt and bring to a boil over medium-high heat. Cover and cook over medium heat, stirring occasionally, until vegetables are tender, about 25 minutes.
Puree in pot with hand held immersion blender or let cook slightly, then puree in batches in blender until smooth. Stir in remaining Plant-Based Butter, thyme, lemon juice and season if desired with salt and freshly ground black pepper. Top each serving with about 1 Tbsp. caramelized shallots and garnish with thyme sprigs if desired.