4 cups sliced Yukon Gold or russet potatoes (about 3–4 potatoes; you can also use cauliflower for a lighter soup!)
4 cups chicken stock, divided
1 tbsp white wine or sake, or more to taste
1 tsp chopped fresh thyme (about 2 sprigs)
1/4 cup Vermont Creamery crème fraîche, or more to taste (see Notes for substitutions)
salt and pepper to taste
for the pancetta breadcrumbs:
1 tbsp olive oil
1 tsp minced garlic (use the tops from the roasted garlic, above)
1/4 cup finely diced pancetta or bacon
1/4 cup coarse plain breadcrumbs (I used Panko)
salt and red pepper flakes, to taste
fresh parsley (optional)
extra crème fraîche
Preheat oven to 400 degrees F. Trim about 1/2-inch off the top of the head of garlic, exposing all the cloves inside. Save any tips of cloves that are sliced off for the pancetta breadcrumbs. Rub the exposed cloves with a bit of olive oil, just enough to coat, then wrap in foil and bake for 40-45 minutes, or until cloves are soft when poked. Once garlic is done, carefully remove foil and set aside to cool. When cool enough to handle, slide cloves out of their skin and reserve.
Heat a 2- or 3-quart pot over medium heat. When a drop of water dances and sizzles when it hits the pot, add the butter and remaining 1 teaspoon olive oil to the pot, and stir until melted. (Waiting until the pot is hot will help prevent the vegetables from sticking.) Add the thinly-sliced leek and potato. Cook, stirring occasionally, until the vegetables have begun to soften and brown slightly, about 6-8 minutes. If the bottom still sticks, don’t worry — the stock and white wine will loosen any brown bits.
Add 3 cups of the chicken stock, the wine or sake, roasted garlic cloves, thyme, and a generous pinch of salt and pepper. Stir to combine, scraping up any stuck bits from the bottom of the pan. Bring mixture to a boil, and then turn heat down to a bubbling simmer. Cook until potatoes are tender, about 20-30 minutes.
While the soup is simmering, make the pancetta breadcrumbs. Add the pancetta to a cold pan and turn the heat to medium-low. Let pancetta cook slowly until crisp and fat has rendered, about 5-8 minutes. Add the breadcrumbs, salt, and red pepper, then reduce heat to low, cooking mixture slowly until all of the crumbs are an even golden color, about 2-3 minutes.
When the potatoes are tender, puree the soup using an immersion blender or a regular blender (in batches). Stir in the crème fraîche, then thin the soup with the last cup of stock until it reaches your desired consistency. Add more salt as needed, plenty of black pepper (I used at least 1/4 to 1/2 teaspoon), and a splash more of white wine or sake if the soup tastes a bit too heavy or rich. Serve with pancetta breadcrumbs, minced parsley, and extra crème fraîche on top.
A few notes on lighter substitutions: Greek yogurt would work wonderfully in place of some or all of the crème fraîche; you could also use cauliflower instead of potato!