Heat a large pot over medium heat and add the olive oil. Once shimmering, add the chopped onion and sauté until translucent and fragrant, about 5 minutes.
Add the minced garlic to the pot and cook for another minute until it begins to scent the air and becomes slightly golden.
Stir in the diced pumpkin, cooking for 3-4 minutes until it starts to soften and releases a sweet aroma.
Pour in the vegetable broth and add the rinsed lentils, then stir in the cumin, cinnamon, red pepper flakes, and a pinch of salt.
Bring the mixture to a boil, then lower the heat to a gentle simmer. Cover the pot and cook for about 30-35 minutes, stirring occasionally, until the lentils are tender and the pumpkin is falling apart.
Uncover the pot and check the consistency—if it’s too thick, add a splash of hot vegetable broth and stir well. If it’s too watery, let it simmer uncovered for a few more minutes to thicken.
Taste and adjust seasoning with more salt or spices if needed. Squeeze in some fresh lemon juice or garnish with chopped parsley for a bright finish.
Serve the hot stew in bowls, enjoying its creamy texture and fragrant spices as a comforting vegan main dish.