Prepare the Pressure Cooker: Heat the pressure cooker.
Prepare Vegetables: Chop the onion, carrots, celery, and garlic.
Sauté Vegetables: Add olive oil to the cooker, then add the vegetables and sauté. Add sugar, bay leaves, cinnamon, allspice, and stir.
Prepare the Octopus: Clean the octopus, cut into large pieces, and add to the cooker. Stir.
Add Liquids and Spices: Add ouzo, tomato paste, crushed tomatoes, and water. Stir.
Cook: Close the lid, set the valve, and cook for 15 minutes once the pressure is reached.
Add Barley: Release the pressure, open the lid, add the barley, and cook for another 10 minutes, stirring every two minutes.
Season and Serve: Taste for salt, add freshly ground pepper, drizzle with fresh olive oil, garnish with chopped parsley, and serve.