Heat a large pot over medium heat, then add the olive oil until shimmering and fragrant.
Add the diced onion and cook, stirring often, until it becomes translucent and soft, about 5 minutes. The aroma will start to fill the kitchen.
Stir in the minced garlic, cumin, cinnamon, and red pepper flakes, cooking for another 30 seconds until fragrant.
Add the diced pumpkin to the pot, stirring to coat with the spices and aromatics, then cook for 3-4 minutes until it starts to soften slightly.
Pour in the vegetable broth and bring to a gentle simmer. Add the rinsed lentils and stir to combine.
Lower the heat to medium-low, cover the pot, and cook for about 25-30 minutes, stirring occasionally, until the pumpkin is tender and the lentils are cooked through. You’ll notice the stew thickening slightly and the pumpkin softening fully.
Once everything is tender, stir in the coconut milk and season with salt and pepper to taste. Let it simmer uncovered for another 5 minutes to let flavors meld and the stew thicken further.
Finish by squeezing in lemon juice for brightness if desired, then taste and adjust seasonings accordingly.
Serve hot, ladled into bowls, with a sprinkle of fresh herbs or extra spices if you like. Enjoy the thick, hearty texture and warming aroma of this unusual pumpkin stew.