Heat a large pot on medium-high heat.
Toss the butter into the pot, and once it's sizzling, stir in the onions.
Brown the onions for a few minutes.
Add the chopped carrots and celery and sauté for two minutes.
Top with the cauliflower florets and garlic, and sauté again for a few minutes.
Add the quartered potatoes and chicken stock, cover, and bring to a boil.
Now, turn down the heat to medium-low.
Let the soup simmer for an additional 20-25 minutes until all the veggies are softened.
Spoon everything into a blender with a big spoon or ladle or use a stick blender directly in the pot.
Blend on low until the soup is creamy.
Pour the soup back into the pot, top with the cream and Worcestershire sauce, and season with sea salt and pepper.
Cook the pancetta in a small pan on medium-high heat until crispy.
Arrange the soup into bowls. Top with sour cream, crispy pancetta, and fresh thyme.