Mushroom Barley Soup with Poached Egg

Ingredients

• • 1 lb (450 g) white mushrooms
  • 2 onions, thinly sliced
  • 2 garlic cloves, chopped
  • 2 tbsp (30 ml) olive oil
  • 3/4 cup (155 g) pearl barley, rinsed and drained
  • 8 cups (2 litres) chicken broth (see note)
  • 1 tbsp (15 ml) Worcestershire sauce
  • 6 cups (140 g) baby spinach
  • 2 tbsp (30 ml) white vinegar
  • 6 eggs