Add 1 tablespoon butter and diced bacon to a dutch oven or large soup pot; cook over medium-high heat for 2 minutes, or until bacon is crispy.
Remove bacon from the pot with a slotted spoon and set aside.
Add remaining butter to the bacon fat in the pot and melt.
Stir in onions and carrots; cook for 2 minutes.
Stir in cauliflower florets, garlic, thyme, chili powder, and parsley.
Season with salt and pepper and cook for 3 minutes, stirring occasionally.
Add chicken broth and bring to a boil.
Lower heat to a simmer and stir in the heavy cream; simmer for 12 to 15 minutes, or until veggies are tender, stirring occasionally.
Puree with an immersion blender OR working in batches, puree in a blender machine; blend until creamy and smooth.
Pour blended soup back into the soup pot; increase heat to medium, add shredded cheddar cheese and nutmeg, then stir until melted.
Taste for seasonings and adjust accordingly.
Remove from heat.
Garnish with previously prepared bacon, shredded cheddar cheese, if using, and chives.