In a pressure cooker, place potatoes, pumpkin, leek, fennel, sage and stock cube. Cover with water.
Seal the cooker and heat. When pressure is reached, reduce heat and simmer 15-17 minutes. Meanwhile, boil the barley in salted water until done, about 20 minutes. Drain.
Take pressure cooker off the heat and release the steam. With an immersion blender, puree the vegetables. If it is too liquid, simmer a few minutes uncovered to reduce.
Add the barley and simmer a few more minutes. Adjust salt if necessary. Serve, drizzled with olive oil and sprinkled with Parmesan.