Peel and finely chop the onion. Peel and dice the carrot. Peel and finely chop the garlic (if using).
Heat 2 tablespoons of water in the base of a large saucepan. Add the onion and carrot. Sauté for 5 minutes over a medium heat until they start to soften.
Add the garlic and a pinch of salt. Cook for another 2 minutes.
Add the red lentils and tinned tomatoes. Stir well to combine.
Pour in the hot vegetable stock or water and add the marmite to the pan. Stir well to dissolve the marmite whilst it comes to the boil.
Reduce the heat and pop on the pan lid. Simmer for 20 minutes until the lentils are well cooked.
Turn off the heat and season to taste with salt and pepper.
Blend with a stick blender to make the soup smooth or just serve as it is. Add more stock or water if it’s too thick.
Store any leftovers in an air-tight container in the fridge for up to 3 days. Or pop in the freezer – just remember to label it.
For more budget friendly cooking tops check out our Real Foods for Real Budgets resource here.