Rinse the shrimp under cold water and pat dry with a paper towel. Set aside.

In a large skillet or pan, heat the vegetable oil over medium heat. Add the cumin seeds and sauté for about 30 seconds until they begin to crackle.

Add the finely chopped onion to the pan. Sauté for 5-7 minutes until the onions are golden brown.

Stir in the minced garlic and grated ginger. Cook for an additional 2 minutes until fragrant.

Add the chopped tomatoes, turmeric powder, coriander powder, and slit green chilies. Cook for about 10-12 minutes until the tomatoes break down and the mixture thickens.

Stir in the garam masala and salt to taste. Cook for another 2-3 minutes, allowing the spices to blend well with the tomato mixture.

Pour in the coconut milk and mix well. Bring the mixture to a gentle simmer.

Add the shrimp to the pan, ensuring they are well-coated with the sauce. Cook for 5-7 minutes, or until the shrimp turn pink and are cooked through.

Stir in the lemon juice for a fresh burst of flavor. Taste and adjust seasoning if needed.

Turn off the heat and garnish with freshly chopped coriander leaves.

Serve the shrimp masala hot with steamed rice or naan bread.