Melt the butter in a large pot over medium-high heat.
Add in the shallots and garlic head. Simmer until garlic is browned and mixture is fragrant.
Add in the potatoes, leeks, and vegetable broth. Simmer for twenty minutes.
Add in the bay leaves, salt, pepper, and other herbs. Simmer for an additional twenty minutes.
Mash the potatoes.
When the potatoes are soft enough to smash, use a large spoon against the side of the pot to slowly mash them and blend them back into the soup.
Add in the carrots and celery. Cook for an additional ten minutes.
Add in the sour cream and cook for 5 more minutes.
Add all toppings, and serve warm.