Place the kombu into 1.5 litres of boiling water and allow it to steep for about one minute to release its flavour into the stock. Add the bonito flakes and let the mixture infuse for about one minute to extract their flavour.

After a minute, stir the miso paste into the liquid until completely dissolved.

Strain the liquid through a fine sieve into a clean saucepan, discarding the kombu and bonito flakes. This dashi stock can be prepared ahead of time and kept warm.

To serve, place the prepared wakame and tofu into serving bowls. Ladle the hot miso soup directly over the top, then garnish with the finely sliced spring onions. Serve immediately.