Heat the coconut oil in a large pot over medium heat. Add the diced onion and cook for 4 minutes until softened.
Stir in the minced garlic and grated ginger. Cook for 1 minute until fragrant.
Add the sliced mushrooms and cook for 5 minutes until they release liquid and start to brown.
Mix in the rinsed red lentils, turmeric, cumin, and garam masala. Stir to coat everything evenly.
Pour in the coconut milk and vegetable broth. Add the salt and bring the mixture to a gentle simmer.
Cover the pot and cook for 20 minutes, stirring occasionally, until the lentils are soft and the stew thickens.
Taste and adjust salt if needed. Serve hot with chopped cilantro sprinkled on top.