Bring a large pot of salted water to a boil. Add the potatoes and cook, uncovered, for about 20 minutes, until the potatoes are fork tender. Drain the potatoes and put them in a mixing bowl while they are still nice and hot. Add the chopped mint and mash so the potatoes are chunky and green in spots. Fold in the butter and stir everything together so the butter melts. Drizzle with the olive oil and season with a healthy amount of salt and pepper.