Preheat an oven to 400 degrees F and line a baking sheet with parchment paper. Toss the cauliflower florets with olive oil and season with salt and pepper. Spread the cauliflower in a single layer on the prepared baking sheet and roast for 45 minutes, until tender and golden brown.

While the cauliflower roasts heat a 4 qt dutch oven or soup pot over low heat. Add the bacon and cook, stirring occasionally, until the bacon is crispy and the fat has rendered out. Remove 2 tablespoons of chopped bacon from the pot and set aside.

Add the onions to the pot and cook in the bacon fat for 10-12 minutes, stirring occasionally, until golden brown. Then, add the white wine and thyme leaves and cook until most of the wine has cooked out. Once the wine has cooked out, add the chicken broth and cauliflower to the pot and bring to a simmer for 5-10 minutes, until the cauliflower is tender.

Transfer the soup to a high-powered blender or use an immersion blender to puree until very smooth. Return the soup to the pot over low heat and add the sour cream and cheddar. Stir until completely melted and season to taste with salt and pepper.

Ladle the soup into bowls and top with minced chives, sour cream, cheddar, and the reserved crispy bacon. Serve immediately.