Put potatoes in a large pot and cover with water. Add plenty of salt (a big palm full; you'll want the water to be a bit salty). Cover pot and bring to a boil. Cook for 20 - 25 minutes or until the potatoes are very tender. Drain water and return pot to the burner and cook, stirring, for 1 minute or 2 to dry out the potatoes. Do this just until the pot stops steaming. This will give you nice, fluffy mashed potatoes.

Mash with about 1 teaspoon of salt with a potato masher or hand mixer on low – medium speed. Add hot milk and butter and whip with hand mixer on high until very smooth. Add heavy cream or half-and-half if using. Note that you may have to adjust the milk to get the potatoes to the desired consistency, so it is best to add a bit at a time until they are just the way you like them. You can keep the potatoes warm by putting them in a bowl over a big pot of simmering water while you prepare the clams.

Wash and scrub the clams.

In a large pot over medium heat melt 2 tablespoons of butter with 1 tablespoon of olive oil. Add the shallots and garlic and cook for about 3 or 4 minutes until they are translucent. Add the clams and pour over the bottle of wine. Turn heat up to high, cover the pot and bring to a boil. Steam clams for about 5 minutes or until the clams just open. With a slotted spoon remove the clams from the pot to a large bowl. Discard any that do not open. Cover with foil to keep warm.

Boil the wine mixture for about 4 or 5 minutes to reduce it a little. Whisk in the remaining 4 tablespoons of butter.

Divide the potatoes between six bowls or deep plates. Top each serving with clams. Ladle the sauce over each serving. Top with any or all garnishes and enjoy!