In a small, dry, heavy skillet over moderate heat, toast the cumin seeds until fragrant, 3 to 4 minutes. Finely grind in a spice grinder or mortar and pestle. Mash the garlic to a paste and transfer half the garlic to a medium bowl. Whisk in the curry paste, 1 cup yogurt and half the cumin. Transfer the chicken to a plastic re-sealable bag and pour the yogurt mixture into the bag, making sure all the chicken is covered. Marinate in the refrigerator for at least 12 hours and up to 24 hours.
Preheat the oven to 425 degrees F.
Line a sheet pan with aluminum foil and top with a cooling rack.
Remove the chicken from the marinade, place on the cooling rack in the sheet pan. Bake until cooked through, 30 to 35 minutes.
In a small bowl, whisk the remaining 1 cup yogurt and the remaining garlic and cumin. Serve a dollop of sauce on top of the chicken.
What really makes this recipe sing: Toasting and grinding your own spices here, makes all the difference in the world. If you don't remember when you bought that jar of cumin, then you should throw it out and start fresh.