Finely grate or very finely chop the onion and squeeze out excess water if it feels very wet. Finely mince the garlic, grate the ginger, and finely chop the green chili (if using) and cilantro.

Combine meatball mixture

In a large bowl combine the ground lamb and ground beef. Add the grated onion, minced garlic, grated ginger, chopped green chili, chopped cilantro, breadcrumbs, beaten egg, ground cumin, ground coriander, garam masala, turmeric, red chili powder, 1.5 tsp salt and 1/2 tsp black pepper. Mix with your hands or a spatula until just combined; avoid overworking to keep the meatballs tender. If the mixture feels too wet, add up to 2 tablespoons more breadcrumbs; if too dry, add 1 tablespoon water or a touch more beaten egg.

Shape meatballs

Portion the mixture into even pieces and roll into meatballs about 1 to 1 1/4 inches (2.5–3 cm) in diameter (makes roughly 20–24 meatballs). Place on a tray or plate and refrigerate for 15–20 minutes to help them hold their shape.

Cook meatballs

Heat a large skillet over medium heat and add 2 tablespoons vegetable oil. When hot, add the meatballs in a single layer without crowding (work in batches if needed). Cook, turning occasionally, until brown on all sides and cooked through, about 8–10 minutes total depending on size (internal temperature 71°C / 160°F). Remove cooked meatballs to a paper-towel–lined plate. If you like, add the remaining 1 tablespoon oil between batches.

Finish

Return all meatballs to the pan for 1 minute to reheat and splash with 1 teaspoon lemon juice. Taste and adjust seasoning with extra salt or pepper if needed. Keep warm while you prepare the sauce and serving elements.

Cucumber & Mint Yogurt Sauce

Prepare cucumber: If using a watery cucumber (e.g., English or garden), grate or finely dice it, then squeeze out excess liquid with your hands or a towel. For a firmer texture, leave some moisture.

Combine sauce: In a bowl whisk the yogurt until smooth. Stir in the prepared cucumber, chopped mint, chopped cilantro, 1 tsp lemon juice, 1/2 tsp salt, 1/4 tsp black pepper and 1/4 tsp toasted cumin powder (if using). Taste and adjust seasoning. If desired, drizzle 1 tsp olive oil on top. Chill until ready to serve.

Garnish & Serving

Serve warm meatballs spooned over or alongside rice or naan. Dollop or drizzle the cucumber-mint yogurt sauce over the meatballs or serve on the side for dipping.

Garnish with extra chopped cilantro and lemon wedges. Offer additional garam masala or chili flakes at the table for those who want more heat.