Place the potatoes into a large saucepan. Add cold water to the pan until the potatoes are covered by at least an inch. Add the salt and garlic cloves.
Turn the heat to high and bring to a boil. Reduce the heat to low to maintain a simmer, and continue to cook until the potatoes are fork-tender - about 15 - 20 minutes.
Add the butter and stir until melted and combined. Add the cream, pumpkin, and spices, and stir until smooth and combined. Taste and adjust with salt and pepper.