Step 1: Heat the olive oil or ghee in a large pot over medium heat. Add the diced onion and sauté for 5-7 minutes until soft and translucent.
Step 2: Stir in the garlic, ginger, turmeric, and cumin. Cook for 1 minute until fragrant.
Step 3: Add the rinsed red lentils, pumpkin purée, and vegetable broth to the pot. Stir well to combine.
Step 4: Bring the mixture to a boil, then reduce the heat to low. Cover and simmer for 15-20 minutes, or until the lentils are tender and have started to break down.
Step 5: While the dal is simmering, prepare the tempering (optional). In a small skillet, heat a teaspoon of oil and add mustard seeds. Once they begin to pop, remove from heat.
Step 6: Stir the dal and season with salt and pepper. Pour the tempering over the dal and stir gently.
Step 7: Serve hot garnished with fresh cilantro and a squeeze of lime juice.