Cook the bacon in the Dutch oven until crispy and then remove it and set aside.
Add in the onion and sauté for about 2 minutes. Now add in the leeks and garlic and sauté for another 2 minutes, stirring constantly.
Add in the butter and cook for another 3-4 minutes stirring constantly.
Add in the chicken broth and deglaze the pan, scrapping the brown bits from the sides and the bottom as you go.
Add in the potatoes, salt, pepper, thyme and bay leaves. Give it all a good stir and cover the pot for 15-20 minutes on low to medium heat. You want this to be lightly boiling because you need the potatoes to be blendable.
When time is up check to make sure the potatoes are very soft. They should be so soft they are starting to fall apart. If they are not, let them continue for another 5 minutes. Then remove the bay leaves and thyme springs when the potato are soft.
Reduce the heat to a simmer. If you're adding the cream, add it now.
Blend with an immersion blender or a stand blender. If you are using a stand blender you will need to blend it in parts.
Once everything has been blended, heat on a simmer for about 10 minutes. Season to taste with salt and pepper.
Serve immediately with desired toppings. (I highly suggest thyme and the bacon and a little cheese!)