Melt the butter in a Dutch oven or large stock pot over medium heat.
2 tablespoons butter
Add the leeks and cook, stirring often, about 5-7 minutes or until tender.
4 leeks
Stir in the garlic and cook an additional 30 seconds.
2 cloves garlic
Carefully pour in the white wine and cook until reduced by half, scrapping up any browned bits from the bottom of the pot.
1/4 cup white wine
Add the chicken stock, potatoes, fresh thyme and bay leaves. Raise the heat and bring to a boil, then cover and lower the heat to simmer.
7-8 cups chicken stock, 2 pounds potatoes, 2 sprigs fresh thyme, 1-2 bay leaves
Continue to simmer until the potatoes are fork-tender, about 10-12 minutes.
Puree with an immersion blender or transfer to a stand blender and puree until desired level of creaminess is reached. You will likely have to work in batches if using a stand blender.
Stir in the cream and cook another minute or so to warm through.
1/4 cup heavy cream
Taste and adjust seasoning, as needed.
Serve with additional fresh thyme and freshly cracked black pepper, if desired.