4 strips thick-cut bacon, cut into 1-inch pieces
2 tablespoons unsalted butter
1 medium onion, diced
3 medium garlic cloves garlic, minced
2 heads garlic, rinsed, papery skins removed and top third of heads cut off and discarded
6 – 7 cups low-sodium chicken broth
2 bay leaves
1 1/2 lbs russet potatoes, peeled and cut into 1/2-inch cubes
1 lb Red Bliss potatoes (unpeeled), cut into 1/2-inch cubes
1/2 cup heavy cream
1 1/2 teaspoons minced fresh thyme leaves
1/4 cup minced fresh chives
Set a large saucepan or Dutch oven over medium heat and add the bacon. Cook until crisp, stirring occasionally, then transfer to a paper towel-lined plate. Drain all but 1 tablespoon of the bacon fat from the pot.
Add the butter and give it a minute to melt, then add the onions and cook until they’ve softened, about 5-8 minutes. Stir in the minced garlic and cook just until fragrant, about 30 seconds to 1 minute. Add the garlic heads, 6 cups of the chicken broth, bay leaves and 3/4 teaspoon salt. Increase the heat to medium-high, partially cover the pot the bring the soup to a simmer. Reduce the heat to maintain a simmer and continue cooking until the garlic is very tender when pierced with the tip of a knife, about 30-40 minutes. Add the potatoes and continue simmering (still partially covered) until the potatoes are fork-tender, about 15-20 minutes.
Remove the bay leaves and discard. Remove the garlic heads, and squeeze at the root end so the cloves slip out of the skins (the heads will be hot, it’s easier if you hold them with paper towels or tongs to do this). Use a fork to mash the garlic cloves into a smooth paste.
Mix the cream, thyme and half of the garlic paste into the soup. Continue cooking until hot, about 2 minutes. Taste the soup and decide if you want to add the remaining garlic paste (we used all of it). Turn off the heat under the pot and puree the soup with an immersion blender (or, if you don’t have one, in a traditional blender – you’ll probably want to do it in a few batches.) I left some chunks of potato so the soup had more texture, but you could process it further if you want. You can thin the soup with the remaining 1 cup of chicken broth if desired – I left mine thick.
Season the soup to taste with salt and pepper and serve, garnished with the garlic chips, chives, bacon, or your favorite garnish.