- On a work surface, cut 3/4 lb (340 g) of the mushrooms into thick slices. Set aside for the soup.
- Thinly slice the remaining mushrooms on a mandoline. Set aside for the garnish.
- In a large pot over medium heat, soften the onions and garlic in the oil. Add the thick slices of mushrooms. Cook until lightly browned. Add the barley and cook for 1 minute. Add the broth and Worcestershire sauce. Bring to a boil. Simmer over low heat for 30 minutes or until the barley is tender. Remove the pot from the heat. Add the spinach. Adjust the seasoning and set aside.
- In another pot of salted simmering water, add the vinegar. Break the eggs, one at a time, into a saucer and gently slide into the water. Poach for 3 minutes or until the desired doneness. The yolks should stay runny. Drain the eggs on a plate.
- Serve the soup in bowls and garnish with the thinly sliced mushrooms. Place an egg at the centre of each bowl and season with pepper. Serve with toast, if desired.
We recommend using a homemade or store-bought broth that has no salt added. This gives you more control over the amount of sodium in the recipe.