In a large pot, warm the vegetable oil over medium heat. Once the oil is shimmering, add the finely chopped onion. Sauté for approximately 5 minutes, stirring frequently, until the onion becomes translucent and soft.
Incorporate the minced garlic and grated ginger into the pot. Continue to sauté for an additional 2 minutes until the mixture is fragrant and the garlic is lightly golden.
Sprinkle the curry powder, turmeric, and cumin into the pot. Stir well to coat the onions in the spices, allowing them to toast slightly for about 1 minute, which enhances their flavors.
Pour in the diced tomatoes (including their juices) along with the vegetable broth. Stir thoroughly to combine all the ingredients, creating a uniform mixture.
Gently add the rinsed red lentils into the pot, stirring to ensure they are well integrated into the mixture.
Increase the heat to bring the mixture to a boil. Once boiling, lower the heat to a gentle simmer. Cook uncovered for about 20 minutes, or until the lentils are tender and the curry has thickened, stirring occasionally to prevent sticking.
After the lentils are cooked through, stir in the coconut milk and fresh spinach leaves. Cook for another 5 minutes, allowing the spinach to wilt and the flavors to meld beautifully.
Taste the curry and season with salt and freshly ground black pepper to your preference, making adjustments to suit your flavor profile.
Serve the curry hot, ladling it into bowls and garnishing generously with fresh chopped cilantro on top for a burst of freshness.
Notes
Serve with warm naan or rice and a slice of lime for added freshness.