Place the clams in a large bowl, fill with cold water and let soak for 5 minutes. Slightly agitate the clams with your hands so they release any sand, which will drop to the bottom of the bowl. Refill the water and repeat this process until no sand remains.
Heat a large saucepan over medium heat. Add the olive oil and 2 tablespoons butter. When the butter is melted, add the onions and saute until translucent, about 3 minutes. Add the garlic, caraway seeds and thyme and continue to cook for 2 minutes.
Add the potatoes, beer and clams and cover. Allow the clams to cook until they are cooked through and open, 5 to 6 minutes. Make sure to shake the pot every 2 minutes or so to agitate the clams to help them to open up and keep them cover in liquid.
Using a slotted spoon, transfer the cooked clams to a large bowl. Discard any unopened clams. Continue to simmer the cooking liquid uncovered until the sauce is slightly reduced, 6 to 7 minutes.
Take the liquid off the heat, stir in the chopped parsley and remaining tablespoon butter. Season to taste with salt and pepper. Place the clams in individual bowls, cover with the liquid and serve with crusty bread on the side.
Cook's Note: If you can't find clams, mussel will also work for this recipe.