Step 1: In a large pot, heat the olive oil over medium heat. Add the onion and sauté for 5-6 minutes until translucent.
Step 2: Stir in the garlic and ginger, cooking for another minute until fragrant. Add the cumin, turmeric, and smoked paprika, stirring constantly for 30 seconds to bloom the spices.
Step 3: Add the cubed sweet potatoes and red lentils to the pot. Stir well to coat them in the spice mixture.
Step 4: Pour in the vegetable broth. Increase heat to high and bring to a boil, then reduce heat to low, cover, and simmer for 20-25 minutes or until the lentils and potatoes are soft.
Step 5: Use an immersion blender to partially blend the soup to your desired consistency. Season with salt and pepper, and stir in a squeeze of lemon juice before serving.