Cut lamb into 1-inch pieces for kebabs.
Whisk yogurt, lemon juice and all spices in bowl until combined.
Toss lamb pieces into yogurt mixture, coating.
Cover and let marinate overnight or at least four hours.
Skewer 3 to 4 pieces on short skewers, grill on medium heat until medium rare.
Plate two kebabs atop a generous dollop of cardamom hollandaise on each plate alongside a serving of cucumber salad.