Lentil Soup

The everyday thermos soup: brown lentils that hold their shape until lunch, and what to thin it with when you reheat.

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Brown lentil soup that still looks like soup at noon instead of paste. What to read on the stock and the lentils, and a red lentil version at the bottom.

Makes
4 lunches
Hands on
20 min
Start to finish
50 min
Keeps
4 days in the fridge, 3 months in the freezer

What you need

Check the label
  • 1 cupbrown or green lentilsNot red. Red lentils collapse into puree, which is the variation at the bottom of this page and not this soup.
  • 4 cupsgluten free chicken or vegetable stockThe one line on this list that can carry wheat or barley.
  • 2carrots, diced smallSmall enough that a spoon can get a piece of carrot and a lentil in the same bite.
  • 2celery stalks, diced small
  • 1yellow onion, diced
  • 3garlic cloves, minced
  • 1 can (14.5 oz)diced tomatoes
  • 2 tablespoonsolive oil
  • 1 teaspoondried thyme
  • 1bay leaf
  • 1 tablespoonred wine vinegarGoes in at the end. Lentils flatten out overnight in the fridge and the vinegar is what brings them back.
  • salt and black pepper

How to make it

  1. Heat the olive oil in a heavy pot over medium. Cook the onion, carrot and celery with a pinch of salt for about 8 minutes, until the onion turns soft and clear.
  2. Add the garlic, thyme and bay leaf. Cook one more minute.
  3. Tip the lentils onto a plate and look them over for stray grains and small stones, then rinse them and add them to the pot with the tomatoes and stock.
  4. Bring to a boil, drop the heat to a low simmer, set the lid on slightly askew and cook 25 to 30 minutes. Taste a lentil at 25 minutes. You want tender and still whole, not falling apart.
  5. Pull the bay leaf out. Stir in the vinegar, then salt and pepper. It will take more salt than you expect.
  6. Let the pot sit uncovered on the counter for 20 minutes before it goes in the fridge. A hot pot with the lid on stays warm in the middle for hours.

Getting it there

the part the other recipes leave out
  1. Reheat it to a full simmer, and preheat the thermos while it heats. Soup poured in warm is cold soup at noon.
  2. Thin it when you reheat. Lentil soup sets up thick overnight, and thick soup at the bottom of a tall thermos is work for a child with a spoon. Taste it again after you thin it, because water flattens the salt.
  3. Crackers, cornbread and corn chips go in their own container. In with the soup they are paste by 11am.
  4. Freeze half the batch in single lunch portions. Moved to the fridge at bedtime, one reheats in about the time the thermos takes to preheat.

What goes wrong

  • It arrives lukewarm. The thermos went in cold, or the soup was warm rather than simmering when it was poured.
  • The lentils are mush and the whole thing is one color. Red lentils by mistake, or a hard boil instead of a low simmer.
  • It tastes like nothing at the table. Soup flattens out in the fridge overnight and it was never tasted again after reheating.
  • There is soup inside the lunch bag. Broth on the threads kept the gasket from seating.

The gluten free part

The stock is the label check on this page and it is a real one. Cubes, pastes and concentrates are where wheat turns up in a soup pot: some list hydrolyzed wheat protein outright, and others carry a yeast extract made from barley, which does not have to appear in a Contains line the way wheat does. Buy a carton or a cube with a gluten free claim printed on the package, and read the one in your hand rather than trusting a brand you bought last year, because these get reformulated. The lentils are the second check, and it is a physical one rather than a label. Lentils are grown in rotation with wheat and cleaned on shared equipment, so buy a bagged brand carrying a gluten free claim instead of scooping from a bulk bin, and tip them onto a plate to pick out stray grains before they go in. Onion, carrot, celery, canned tomatoes and plain dried thyme have nothing to read.

Worth doing

For a different soup out of the same pot, use red lentils instead of brown, add a teaspoon of turmeric and a teaspoon of ground cumin with the garlic, leave out the tomatoes, and cook 20 minutes until it collapses into something closer to a dal. It travels better than the brown version because there is nothing left in it to overcook.