Peel the pumpkin and cut into 2cm chunks. Discard the dark green top from the leek. Halve the leek lengthwise, rinse under running water to remove any hidden dirt, then thinly slice.
Step 2 — Prep stock
Crumble the stock cubes into a small saucepan. Add 500ml (2 cups) boiling water and stir to dissolve.
Step 3 — Start soup
Add the pumpkin, leek, coconut milk and red galangal seasoning to the stock and stir to combine. Season lightly with salt and pepper and bring to the boil.
Step 4 — Simmer soup
Reduce the heat to medium-high and simmer the soup for 12 mins or until the pumpkin is tender.
Step 5 — Prep toppings
Meanwhile, finely chop the cashews. Pick the coriander leaves, discarding the stems.
Step 6 — Blend soup and serve
Blend the soup with a stick blender until smooth (take care when blending hot soup as the mixture may spit). Taste, then season with salt and pepper. Divide the soup among bowls and scatter with the cashews and coriander to serve.