Heat the oven to 400 F. Pierce the potatoes all over with a fork, place on a foil-lined sheet pan and bake for 1 hour or until potatoes are tender. Alternatively, wrap the potatoes in damp paper towel and microwave 8-10 minutes or until soft.

While the potatoes are roasting, heat the oil in a large skillet over medium-high heat. Add the onion and cook until softened and lightly browned, about 8 minutes. Stir in the turmeric, vinegar and salt and pepper and cook 2 minutes longer. Stir in the grapes and turn off the heat.

When potatoes are done, cut off the top quarter of each potato, fluff the insides with a fork.  Top with the onion mixture, pepitas, cilantro and mint and sprinkle with feta. Serve.