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Dinner · Part 2 of 3: Instructions

Slow Cooker Green Lentils with Carrots and Wholegrain Mustard Step-by-step instructions

A close-up of a bowl filled with slow-cooked green lentils, carrots, and onions in a savory, glossy mustard broth.
Prep
Cook
Total
Serves
4
Includes 5 min resting

Before you start

Before starting, ensure all vegetables are cleaned thoroughly under running water. Peel the carrots and remove the ends before slicing them into consistent, bite-sized rounds to ensure even cooking. Similarly, peel the onion and chop it into uniform pieces.

If using dry lentils, inspect them quickly for any small stones or debris, then rinse them under cold water in a fine-mesh sieve until the water runs clear to remove any excess starch. Having all ingredients prepped and ready to go before you begin the layering process makes the assembly quick and efficient.

Ingredients at a glance (5)
  • 1 cup green lentils, rinsed
  • 2 medium carrots, sliced
  • 1 medium yellow onion, chopped
  • 1 cube vegetable bouillon cube, crumbled
  • 2 tbsp wholegrain mustard

Instructions

Layering the Base

  1. Assemble the Ingredients
    Place the rinsed green lentils into the slow cooker basin. Evenly layer the sliced carrots and chopped onions over the top of the lentils. Sprinkle the crumbled vegetable bouillon cube over the vegetables to ensure even flavor distribution throughout the cooking process.
    Look for Ingredients are layered neatly inside the slow cooker.
    Tip Layering the ingredients helps the lentils cook evenly in the liquid without sticking to the bottom.

At this stage, the slow cooker contains a neat arrangement of dry lentils topped with colorful carrots, onions, and the crumbled bouillon cube. The ingredients should be distributed evenly across the bottom of the vessel to ensure uniform heat distribution. Ensure that the bouillon is crumbled finely so that it dissolves effectively once the liquid is added, preventing any concentrated pockets of salt or seasoning in the final dish. The arrangement should look organized and ready for the liquid component.

Adding the Mustard Broth

  1. Prepare the Mustard Broth
    In a glass measuring pitcher, combine the necessary amount of liquid with the wholegrain mustard, whisking until the mustard is fully incorporated. Carefully pour this mixture over the layered vegetables and lentils in the slow cooker, ensuring all ingredients are mostly submerged for proper hydration.
    Look for Liquid covers the dry ingredients completely.
    Tip Whisking the mustard into the liquid beforehand prevents clumps and ensures a consistent flavor in every bite.

The mixture now includes the liquid base, which should cover the dry ingredients completely. The presence of the mustard should be visible as a light, textured swirl within the liquid, promising a flavorful outcome once the cooking process is initiated.

Check that all the lentils are submerged beneath the liquid to ensure they cook evenly. The mixture should appear well-mixed and ready to be covered, with the mustard distributed throughout the pot to provide consistent seasoning to the lentils and vegetables.

Final Slow Cooking

  1. Slow Cook and Serve
    Cover the slow cooker with its lid and cook on the low setting for approximately 4 hours, or until the lentils are tender and have absorbed most of the flavorful broth. Once cooked, give the mixture a gentle stir, let it rest for 5 minutes, and serve warm in bowls.
    Look for Lentils are tender and the liquid has reduced to a thick, glossy consistency.
    Tip Checking the texture of the lentils ensures they are cooked through but not mushy.

The dish is finished when the lentils have softened significantly and the liquid has reduced to a thick, savory sauce. The mixture should appear glossy and fragrant, with the carrots fully cooked and the onions translucent and tender throughout the pot.

Before serving, give the mixture a gentle stir to incorporate any remaining liquid into the lentils, creating a cohesive and flavorful dish. The aroma should be savory and slightly tangy, indicating that the mustard has successfully infused the entire mixture.

Common mistakes

Avoid overcooking the lentils, as they can become mushy if left in the slow cooker for too long after they reach tenderness. Additionally, ensure the lid is kept tightly closed throughout the cooking process to maintain the necessary heat and moisture levels, as frequent lifting of the lid will significantly increase the total cooking time and cause uneven results.

Do not add too much liquid at the start, as the vegetables will release their own moisture, which is essential for achieving the correct final texture of the dish.

How to tell it’s done

The lentils are done when they are tender enough to be easily pierced with a fork but still retain a slight bite, rather than turning into a puree. The carrots should be soft and easily cut with a spoon. The overall consistency should be thick and glossy, with the mustard-infused liquid coating the lentils rather than being watery. There is no protein to monitor for temperature, so focus entirely on the texture of the lentils and the reduction of the liquid to ensure the desired final consistency.

Coming up in Part 3: common questions

  • Can this be made in a regular pot on the stove?
  • Is it necessary to soak the green lentils before cooking?
  • Why do the lentils turn mushy?

Also in Part 3: variations (Herbed Lentils, Spicy Mustard Lentils), storage and make-ahead, and the printable recipe card.

Up next · Part 3 of 3

2 variations · storage & make-ahead · 3 answers · printable card

Tips, FAQ & printable recipe (Part 3)← Back to the ingredients (Part 1)