4 large floury potatoes (in the U.S., use baking potatoes; in the U.K, use Maris Pipers)
4 tablespoons butter
½ cup creme fraiche
1.5 tablespoons salt
freshly ground black pepper
1 tablespoon truffle oil
Wash, peel and cut potatoes into 1.5 inch to 2 inch chunks. Place the potatoes in a large stock pot, cover the potatoes with cold water until the level of the water is about 1 inch above the potatoes. Add a sprinkling (about ½ teaspoon) of salt, cover and bring to a boil over high heat.
Boil potatoes until easily pierced with a fork, about 10-12 minutes. Drain potatoes in a colander and set the colander over the pan you cooked the potatoes in to let the potatoes dry a bit (this is called steam-drying).
Heat and oil an outdoor grill or on a stovetop grill pan over medium-high heat. Add sausages and grill on both sides until fully cooked. If you're using a grill pan, sear both sides of the sausages over medium high heat, then add a ½ cup of water and let the water boil off until completely evaporated.
While the sausages are cooking, take the colander off the stockpot and melt the butter in it over medium-low heat. Tip the stockpot so that the butter slides to one side of the pot and add the potatoes back in to the other side. Gradually mash the potatoes (either with a potato masher or a fork), bringing in the butter as you mash the potatoes.
Once the butter and the potatoes are fully incorporated, gently fold in the creme fraiche and salt, then season with pepper and salt, if necessary. Drizzle truffle oil over the mashed potatoes and serve immediately with the sausages.
Recipe by Grits and Chopsticks at https://www.gritsandchopsticks.com/the-gravy-train/2017/03/grilled-sausages-and-truffled-mashed-potatoes.html