Heat a large stockpot or Dutch oven over medium high heat. Add bacon and cook until brown and crispy, about 6-8 minutes. Transfer to a paper towel-lined plate, reserving 1 tablespoon excess fat in the stockpot.
Melt butter in the stockpot. Add garlic and onion, and cook, stirring frequently, until onions have become translucent, about 2-3 minutes. Stir in thyme until fragrant, about 1 minute.
Whisk in flour until lightly browned, about 1 minute. Gradually whisk in milk, vegetable stock, clam juice and bay leaf, and cook, whisking constantly, until slightly thickened, about 1-2 minutes. Stir in potatoes.
Bring to a boil; reduce heat and simmer until potatoes are tender, about 12-15 minutes.*
Reduce heat to low. Stir in half and half and clams until heated through, about 1-2 minutes; season with salt and pepper, to taste. If the soup is too thick, add more half and half as needed until desired consistency is reached.
Serve immediately, garnished with bacon and parsley, if desired.
Notes
Start with a smoky base. A good clam chowder starts with a smoky base, beginning with the bacon and sautéing the aromatics (garlic and onion) right in the bacon fat.
Use the reserved juices. The juices from the canned clams add all the extra, deep clam flavor.
Russet potatoes serve as a natural thickener. The potatoes will release starch into the broth to create that velvety, restaurant-quality richness.
Use half and half or heavy cream. Half and half will yield a thinner soup whereas heavy cream will result in more of a rich, velvety, indulgent clam chowder.
Always add the dairy at the very end. Avoid boiling the half and half or heavy cream, adding it in at the end of cooking time (or else it will curdle).
Avoid overcooking the clams. Similar to the half and half, add the clams during the last few minutes of cooking. Overcooked clams can be rubbery!
Simmer, simmer, simmer. The longer it simmers, the more it thickens, making it perfect to cook until the desired consistency is reached.
Make it clammier. For those wanting extra clam flavor, add an additional can of chopped clams.
Serve with crusty bread. Serve with all the homemade crusty bread or cornbread for dipping, sopping and dunking!
Reheat gently. Leftovers can be reheated gently over low heat, adding a splash of milk, half and half or stock as needed.