Heat the olive oil in a large heavy-bottomed pot over medium heat.
Add the diced onion and sauté for 5 minutes until translucent and soft.
Stir in the garlic, grated ginger, cumin seeds, and red pepper flakes; cook for 60 seconds until highly fragrant.
Add the sliced carrots and rinsed red lentils to the pot, stirring for 2 minutes to incorporate with the aromatics.
Pour in the vegetable stock and increase heat to bring the liquid to a boil.
Reduce heat to a low simmer, cover the pot, and cook for 20 to 25 minutes until the carrots and lentils are completely tender.
Using an immersion blender, process the soup until a smooth and creamy consistency is achieved.
Stir in the lemon juice and season with salt and black pepper.
Ladle into bowls and garnish with fresh cilantro before serving.