Heat olive oil in a heavy-bottomed pan. Add the onion and cook over medium heat 8 minutes until translucent but not browned. Add the garlic, cubed pumpkin and the splash of wine. Cover and cook a couple of minutes.
Add the barley and stir well. Cook 2 minutes. Add the sage and salt and pepper to taste. Add the stock all at once, bring to a boil and reduce to a simmer.
Cook 30 minutes until liquid is absorbed and barley is tender, stirring occasionally. Serve with Parmesan.