Barbecued flounder with pine nut, garlic and golden sultana dressing

Ingredients

• 1 medium-sized onion, sliced
• 3 tablespoon extra-virgin olive oil, plus extra for barbecuing
• 3 tablespoon pine nuts
• 2 clove garlic, thinly sliced
• 2 tablespoon golden sultanas or raisins soaked for 30 minutes in ½ cup hot water
• 1/2 cup dry white wine
• 3 tablespoon flour
• 1/4 teaspoon salt
• 4 x 400g whole flounder, scaled and gutted
• 2 tablespoon parsley, chopped