Preheat the oven to 400°F.
Wrap beets in aluminum foil & bake for about 75 minutes, or until tender. Refrigerate the beets for 4 to 6 hours. Peel & chop the roasted beets into half inch cubes & set aside.
Whisk the cumin, black pepper & salt into the yogurt in a large bowl. Gently fold the beets into the yogurt along with cashews, ginger, cilantro & lemon juice.
Heat the olive oil in a small pan over medium-high heat & fry the mustard seeds until they pop. Immediately pour the oil & seeds over the yogurt mixture & fold together. Refrigerate until ready to serve.
photo courtesy of Edible Houston: Jenn Duncan