4 large onions, halved and thinly sliced
2 Tablespoons butter
2 Tablespoons vegetable oil
1 Tablespoon dried thyme
3 garlic cloves, crushed
125 ml/1/2 cup dry white wine
1.2 litres/5 cups chicken or vegetable stock or beef stock
sea salt and freshly ground black pepper
Worcestershire sauce, to taste (optional)
finely grated Parmesan crusty baguette
Combine the onions, butter and oil in the pressure cooker. Set on the stove-top over high heat and cook for at least 10 minutes, stirring occasionally, until well colored but taking care not to burn. The onions should be brown, caramelized and aromatic.
Stir in the thyme, garlic and wine and bring to the boil. Boil for 1 minute to cook off the alcohol. If your stock is unseasoned, or lightly seasoned, add about 1 teaspoon salt, or more to taste.
Add the stock. Lock on the lid and bring to high pressure.
Lower the heat slightly but maintain high pressure and cook under high pressure for 7 minutes then let cool naturally. When cool, release and remove the lid, taking care of any steam that is expelled as you open the pressure cooker.
Taste and adjust the seasoning, adding Worcestershire sauce if desired. To serve, ladle into warmed soup bowls and sprinkle with finely grated Parmesan. Serve immediately with thick slices of crusty baguette.