Heat 1 teaspoon oil in a small skillet over medium heat. Add mustard and cumin seeds to pan; cook 2 minutes or until mustard seeds pop, stirring constantly. Remove from heat. Place spice mixture and salt in a mortar; crush seeds with pestle. Set aside.
Gently squeeze potato to remove excess moisture. Combine potato, spice mixture, parsley, 2 tablespoons oil, turmeric, and peppers in a large bowl. Divide mixture evenly into 10 (1/3 cup) portions; place on a baking sheet coated with cooking spray. Flatten to 1/2-inch thickness. Bake at 400° for 16 minutes or until golden. Turn over; bake an additional 5 minutes. Serve with sour cream.