Prepare Aromatics: Heat the vegetable oil in a large frying pan or skillet over medium heat until it shimmers. Add the finely chopped onion and sauté for 5-7 minutes, stirring occasionally, until it softens and turns translucent, emitting a sweet, fragrant smell.

Introduce Ginger and Garlic: Add the minced garlic, grated ginger, and chopped green chilli (if using) to the pan. Cook for another 1-2 minutes, stirring constantly, until you can smell their pungent, aromatic fragrance filling the air, being careful not to let them brown.

Brown the Beef: Add the lean ground beef to the pan, breaking it up with a wooden spoon. Cook for 6-8 minutes, stirring frequently, until the beef is fully browned and no pink remains. The beef should sizzle and release its own juices, turning a deep, rich brown colour. Drain any excess fat if necessary, though with lean beef, this is often not required.

Add Spices: Stir in the ground cumin, ground coriander, turmeric powder, and garam masala. Cook for 1 minute, stirring constantly, allowing the spices to toast and become fragrant. You'll notice a warm, earthy aroma developing as the spices bloom in the hot oil and beef.

Build the Sauce: Pour in the can of chopped tomatoes, beef stock, and stir in the tomato paste. Bring the mixture to a gentle simmer. Season generously with salt and freshly ground black pepper. The sauce will be a vibrant red-orange hue and will start to bubble gently at the edges.

Simmer and Thicken: Reduce the heat to low, cover the pan, and let the curry simmer for 15-20 minutes. This allows the flavours to meld beautifully and the sauce to thicken slightly. Stir occasionally to prevent sticking. The sauce should be rich and glossy, and the beef tender.

Finish and Serve: Remove the pan from the heat. Stir in a generous handful of fresh chopped coriander. Taste and adjust seasoning if needed. Serve the hot, aromatic ground beef curry spooned generously over freshly cooked basmati or jasmine rice.