Heat the olive oil and butter in a large pot over medium-low heat. Add the sliced leeks, sprinkle with kosher salt, and sauté for 8 to 10 minutes, stirring occasionally, until the leeks are soft and beginning to turn translucent.

Add the dried thyme and garlic and sauté for 1 to 2 additional minutes, stirring frequently, until fragrant.

Add the carrots, a pinch or two of salt, and stir the mixture together. Pour in the chicken broth and ½ cup of water, and bring to a boil.

Lower the heat and simmer for 20 to 30 minutes, or until the carrots are very soft and tender.

Transfer the soup to a high-powered blender, and puree until mostly smooth.

Pour the soup back into the pot, heat over low, stir in the heavy cream until incorporated. Add the red wine vinegar. Season to taste with salt and pepper. If the soup is too thick, add a touch of hot water and season again as needed.

Serve hot and garnish with a drizzle of creme fraiche or plain yogurt, drizzle with extra virgin olive oil, and herbs as desired.