Heat the vegetable oil in a large pot over a medium heat. Add the onion and cook for 5-7 minutes, stirring often until softened and starting to brown.
Add the ginger to the pot and cook for 2 minutes, stirring often.
Finely chop the broccoli and add to the pot along with the coconut milk and water. Bring to a simmer, turn the heat down to low and cover the pot with a lid. Let the broccoli cook for 5-6 minutes until completely soft.
Add the peas to the pan and stir through until defrosted.
Remove from the heat and add the coriander and miso. Blend the soup until smooth - either using a hand blender straight in the pot, or by pouring the contents of the pot into a free standing blender. If needed, thin with a little more water and season with salt to taste (the miso added enough salt for my taste)