Prepare the meatball mixture by combining ground beef, minced onion, garlic, grated ginger, cumin, coriander, chili powder, garam masala, salt, cilantro, beaten egg, and breadcrumbs in a large mixing bowl.

Form the mixture into 16-18 uniform meatballs, each about 1.5 inches in diameter. Place them on a plate and set aside.

Heat vegetable oil in a large, heavy-bottomed pan over medium-high heat. Brown meatballs on all sides for 8-10 minutes total. Remove and set aside.

In the same pan, add chopped onions and cook until translucent and lightly golden, approximately 5-6 minutes.

Add minced garlic and grated ginger, cooking for another minute until fragrant.

Stir in all ground spices, cooking for 30 seconds to bloom the spices and intensify flavors.

Add tomato paste and cook for 2 minutes, stirring constantly to prevent sticking.

Pour in diced tomatoes and cook for 5-7 minutes until tomatoes break down and create a thick base.

Slowly add coconut milk and broth, stirring continuously to create a smooth sauce. Bring to a gentle simmer.

Season with salt and pepper, then return browned meatballs to the sauce.

Reduce heat to low, cover partially, and simmer for 20-25 minutes until meatballs are cooked through and sauce thickens.

Taste and adjust seasoning. Garnish with fresh cilantro and red chili slices before serving hot.