Preheat oven to 400 degrees.
In a spice grinder, grind together the cloves and black peppercorns until they are completely ground. Combine ground cloves and peppercorns in a small bowl with coriander, cumin, mustard, fenugreek, cardamom, cinnamon, and turmeric. Stir to combine.
Toss halved potatoes with olive oil until coated evenly. Add in the spice mixture and toss to coat the potatoes. Spread in an even layer on a lined, rimmed baking sheet. Bake for 30 minutes, or until fork tender.
While the potatoes are baking, whisk together yogurt, lemon juice, olive oil and salt.
Remove potatoes from oven and add to the serving dish of your choice. Drizzle the yogurt sauce over the potatoes and sprinkle with fresh chopped cilantro.