Tandoori Champ (Indian Lamb Ribs)

Ingredients

• 2 racks (2 lb.) lamb spareribs (often called Denver ribs)
• 1 tbsp. cumin seeds
• 1 tbsp. garam masala
• 8 cloves garlic, peeled
• 1 (4″-piece) ginger, peeled and thinly sliced
• 1⁄2 cup whole-milk Greek yogurt
• 1⁄4 cup malt vinegar
• 3 tsp. cayenne pepper
• 2 tsp. ground cardamom
• 1 1⁄2 tsp. red food coloring
• 1 tsp. freshly grated nutmeg
• Kosher salt
• freshly ground black pepper
• Juice of 1 lemon, plus wedges for serving
• Melted unsalted butter, for serving