Cook the frozen peas and scallion in boiling water with the stock cube, or stock concentrate, to taste. Make sure the peas are tender.
Drain off the liquid and set it aside. Remove the scallion.
Put the peas in the blender, wait at least 5 minutes before blending. Add the cooled liquid into the blender with the peas. Add some or all of the cheese. I think all the cheese would be too much myself, but it's up to you. Fill the blender to about 1/2 way. Be careful, hot liquids can come out of the top of the blender. Add the rest of the liquid and blend.