Rinse the red lentils under cold water until clear, then soak for at least 6 hours or overnight.

Heat the oil in a deep skillet over medium-high heat, then add garlic, ginger, and serrano pepper. Sauté for about 3 minutes.

Stir in cumin, cayenne pepper, coriander, curry powder, garam masala, turmeric, and season with salt and black pepper. Cook for 30-60 seconds.

Add the soaked lentils, crushed tomatoes, and coconut milk to the skillet. Stir well and lower heat to a simmer.

Simmer on low for 20-25 minutes, stirring occasionally until lentils are soft. Add water if it gets too thick.

Turn off heat and stir in lemon juice and cilantro. Adjust salt to taste.

Serve with basmati rice or naan, and store leftovers in an airtight container.