Wash the Lentils
Rinse the red lentils in a strainer under running water until the water runs clear. Drain and set aside.
Sauté the Vegetables
Heat olive oil in a large stockpot over medium heat.
Add the diced onion and sauté for about 5 minutes, until softened and translucent.
Stir in the diced carrot and potatoes, cooking for another 1–2 minutes.
Add Lentils and Spices
Add the rinsed lentils to the pot, followed by cumin, turmeric, salt, and black pepper. Stir to coat the vegetables and lentils with the spices.
Pour in the Stock
Pour in the vegetable stock, stirring to combine all the ingredients.
Bring the mixture to a boil, then reduce the heat to low. Cover and simmer for 40 minutes.
Blend the Soup
Remove the pot from heat and let the soup cool slightly.
Use an immersion blender to puree the soup until smooth and creamy. Alternatively, transfer the soup to a high-speed blender in batches and blend carefully.
Adjust and Serve
Taste the soup and adjust the seasoning if needed.
Serve hot with a squeeze of fresh lemon juice and optional garnishes like parsley, lemon wedges, or red pepper flakes.