Step 1
Preheat oven to 400 degrees F (200 degrees C).
Step 2
Place potatoes into a large roasting pan and drizzle with 2 tablespoons olive oil. Sprinkle with salt and mix to coat potatoes with salt and olive oil. Turn so the cut sides are up.
Step 3
Roast in the preheated oven for 30 minutes.
Step 4
While potatoes are cooking pour 1 teaspoon olive oil into a large skillet over medium heat and cook pancetta stirring often in the hot oil until pancetta releases some fat and looks like cooked ham about 5 minutes. Stir in king trumpet chanterelle nameko and clamshell mushrooms adding a pinch of salt as they cook.
Step 5
Turn heat to high and cook mushrooms until most of the juices evaporate and mushrooms begin to brown about 10 minutes.
Step 6
Turn oven heat up to 425 degrees F (220 degrees C).
Step 7
Stir potatoes in the baking dish; mix mushrooms and pancetta with potatoes. Return to oven and bake for 10 minutes; stir and continue baking until potatoes are browned soft and tender about 10 more minutes. Let cool slightly about 10 minutes.
Step 8
Drizzle sherry vinegar over potatoes and mushrooms sprinkle with tarragon garlic and 1 tablespoon olive oil and toss to mix. Taste and adjust seasoning. Transfer to a serving platter.