Put the ginger, garlic and onion in a large soup pot with the broth and cayenne.

Bring to a boil then cover, lower the heat and let simmer for 30 minutes.

While the broth is simmering, sauté tofu in 1 Tbsp hot sesame oil until crispy on all sides.

When the broth is ready, add tofu, peas and mushrooms and return to a boil.

Take a ladle of broth and mix with miso in a small bowl until smooth. Add miso to soup.

Take the soup off the heat and add egg in a thin stream while stirring.

Stir in the remaining hot sesame oil, vinegar and tamari.

Serve hot.