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slow cooker red lentil soup 2

Slow Cooker Red Lentil Soup

Maya Chen
A cozy, protein-rich, and incredibly budget-friendly soup that practically cooks itself.
Print Recipe
Prep Time 10 minutes
Cook Time 4 hours
Total Time 4 hours 10 minutes
Course Meal Prep 🫙
Servings 6

Ingredients
  

  • 1-1/2 cups red lentils rinsed and drained
  • 1 medium onion chopped
  • 2 carrots diced
  • 2 celery stalks diced
  • 3 garlic cloves minced
  • 1 can 14oz diced tomatoes
  • 6 cups vegetable broth
  • 1-1/2 tsp ground cumin
  • 1 tsp smoked paprika
  • 1/2 tsp ground coriander
  • 1 tsp salt or to taste
  • 1/2 tsp black pepper
  • 2 cups baby spinach optional
  • Juice of 1 lemon for serving

Optional:

  • coconut milk red pepper flakes

*Ingredient costs are estimated based on bulk purchasing and typical grocery prices.

Instructions
 

  • Prep Ingredients: Rinse the red lentils well under cold water until the water runs clear. Dice the onion, carrots, and celery. Mince the garlic.
  • Load Slow Cooker: Place the diced onion, carrots, celery, and minced garlic in the bottom of the slow cooker insert.
  • Add Liquid & Lentils: Add the rinsed red lentils, canned diced tomatoes (with juice), broth, olive oil (if using), dried thyme, cumin, and bay leaf to the slow cooker. Stir briefly to combine.
  • Cook: Cover the slow cooker and cook on LOW for 7–8 hours or HIGH for 3–4 hours. The soup is ready when the lentils have completely softened and broken down, thickening the soup.
  • Season & Finish: Remove and discard the bay leaf. Season generously with salt and black pepper to taste. If the soup is too thick, stir in a splash of water or extra broth until desired consistency is reached.
  • Serve: Serve hot. Top with a sprinkle of fresh parsley or a dollop of plain Greek yogurt for extra protein (optional).

Notes

Clever Tip

Red lentils break down naturally during cooking, eliminating the need to blend the soup for a creamy texture—a clever trick for saving time!

Meal Prep & Freezing Tips

  • Refrigeration: The soup keeps well in an airtight container in the refrigerator for up to 5 days. It will continue to thicken as it chills.
  • Freezing: This is excellent for long-term prep! Ladle cooled soup into freezer-safe containers or freezer bags (leaving headspace, as liquids expand). Freeze for up to 3 months.
  • Reheating: Thaw overnight in the refrigerator. Reheat on the stovetop, adding a little extra broth or water to adjust the consistency.