Indian Lamb Burgers with Green Raita Sauce and Red Onions

Green Sauce:

• 1 cup plain Greek yogurt
• A handful cilantro leaves
• A handful mint leaves
• 1 clove garlic, peeled and grated or mashed into paste
• Pinch salt
• 1 lime, juiced

Sliders:

• 4 (1/2-inch thick) slices small red onion
• 1 lime, juiced
• Extra-virgin olive oil, for drizzling
• Salt and freshly ground black pepper
• 2 pounds ground lamb
• 2 large cloves garlic, grated or finely chopped
• 1 red or green chile, finely chopped
• 1-inch piece ginger, grated or minced
• 1 teaspoon (1/3 palmful) turmeric, ground cumin, ground coriander, smoked sweet or sweet paprika, granulated onion or onion powder*
• Pinch ground cinnamon
• Baby spinach leaves
• 8 soft potato rolls or slider rolls (recommended: Pepperidge Farm)