# Slow Cooker Red Lentil Soup > Add 300 g rinsed red lentils, onion, carrots, celery, garlic, tomato paste, cumin, smoked paprika and 1.5 litres of vegetable broth to a slow cooker. Cook on LOW for 6-7 hours or HIGH for 3-4 hours, until the lentils fall apart. Blend until smooth, stir in lemon juice and serve topped with pumpkin seeds and herbs. Source: https://www.savourrecipes.com/recipe/slow-cooker-red-lentil-soup Author: Cookwithmrdots | Published: Oct 28, 2026 | Updated: Oct 28, 2026 Categories: Slow Cooker Recipes, Healthy Recipes Collections: Meal Prep Recipes Tags: Vegan, Vegetarian, Gluten Free, Low Calorie, Meal Prep, Make Ahead Red lentils melt as they cook, so this soup turns thick and creamy without a drop of cream. It is a pantry dinner that costs very little, freezes beautifully and gets its brightness from a squeeze of lemon and a handful of toasted pumpkin seeds on top. ## Key facts - Prep time: 15 mins - Cook time: 6 hrs 30 mins - Total time: 6 hrs 45 mins - Yield: 6 servings - Difficulty: Easy - Cuisine: Middle Eastern - Method: Slow cooking - Calories: 280 per serving ## Ingredients - 300 g red lentils, about 1 1/2 cups, rinsed - 1 large onion, chopped - 2 carrots, chopped - 1 stalk celery, chopped - 4 cloves garlic, minced - 2 tbsp tomato paste - 2 tsp ground cumin - 1 tsp smoked paprika - 1/2 tsp ground turmeric - 1/4 tsp chili flakes (optional) - 1 1/2 litres vegetable broth, 6 cups; check it is gluten-free - 1 tsp salt, or to taste - 2 tbsp lemon juice, about 1 lemon - 2 tbsp extra virgin olive oil, for drizzling ### To serve - 3 tbsp toasted pumpkin seeds - chopped parsley or cilantro (optional) ## Equipment - Slow cooker (5-6 litre) - Immersion blender or countertop blender - Fine-mesh sieve ## Instructions 1. **Rinse the lentils.** Rinse the red lentils in a fine-mesh sieve under cold water until the water runs mostly clear, and pick out any small stones. 2. **Load the slow cooker.** Add the lentils, onion, carrots, celery, garlic, tomato paste, cumin, smoked paprika, turmeric, chili flakes and broth to the slow cooker. Stir well so the tomato paste dissolves. 3. **Slow cook.** Cover and cook on LOW for 6-7 hours or on HIGH for 3-4 hours, until the lentils have broken down and the carrots are very soft. 4. **Blend.** Blend the soup with an immersion blender until smooth, or leave it a little chunky if you prefer. If using a countertop blender, work in batches, fill it no more than half full and vent the lid so steam can escape. 5. **Season and serve.** Stir in the salt and lemon juice and taste; add more of either as needed. Thin with a little hot water if it is too thick. Ladle into bowls and top with a drizzle of olive oil, pumpkin seeds and herbs. ## Tips - Add the salt and lemon at the end. Acid added early can keep lentils from softening. - The soup thickens a lot as it cools. Loosen leftovers with broth or water when reheating. - Red lentils do not need soaking, which is what makes this soup so easy. ## Variations - Stir in a 400 ml can of coconut milk after blending for a richer, creamier soup. - Add 2 big handfuls of baby spinach after blending and let it wilt for 5 minutes. - Swap the smoked paprika for 1 tbsp mild curry powder. ## Storage - Fridge: Refrigerate in airtight containers for up to 5 days. - Freezer: Freeze in portions for up to 3 months. Thaw overnight in the fridge. - Reheat: Reheat on the stove over medium heat, stirring and adding a splash of water, until steaming hot. ## Nutrition per serving (estimate) | Calories | Protein | Carbohydrates | Fat | |---|---|---|---| | 280 | 14 g | 40 g | 7.5 g | ## Frequently asked questions ### Do red lentils need to be soaked before slow cooking? No. Red lentils are small and split, so they cook quickly and break down without soaking. Just rinse them well to remove dust and excess starch. ### How long does lentil soup take in the slow cooker? Red lentil soup takes 6-7 hours on LOW or 3-4 hours on HIGH. It is ready when the lentils have completely softened and the carrots are tender. ### Can I use green or brown lentils instead? Yes, but they hold their shape and take a little longer, about 7-8 hours on LOW. The soup will be earthier and more textured, and it will not blend as smooth. ### Is red lentil soup healthy? Yes. Each serving has about 280 calories, 14 g of plant protein and 8 g of fibre, and the soup is vegan, gluten-free and low in saturated fat.