I’ve done this with red, yukon, and my personal favorite, sweet potatoes! > It’s so easy! They are a great “do ahead” for entertaining.
I boil potatoes until just barely soft. Drizzle olive oil and course sea salt on the cookie sheet. Smash potatoes and add more olive oil (and/or melted butter). Sprinkle with more course salts, herbs, parm. cheese or whatever! Roast until crispy on top at a higher heat (425 degrees).