Baked avocado with prawns and white wine dressing

Preheat the oven to 180°C.
Grease a baking sheet.
Place the first four ingredients in a fairly small saucepan and bring to the boil.
Boil until most of the liquid has evaporated and the mixture has been reduced to about 50 ml.
Reduce the heat and add the cream.
Simmer slowly until the sauce begins to change colour. Set aside.
Place an avocado half, cut side down on top of each slice of bread and trim the bread following the outline of the avocado.
Remove the avocado halves and brush the bread shapes lightly with olive oil and sprinkle with the dried mixed herbs. Return the avocado halves to the bread shapes and brush well with mayonnaise.
Bake the avocados for 15 minutes or until the mayonnaise just begins to change colour. Remove immediately.
Meanwhile saute the prawns in a little oil until done.
Arrange the lettuce leaves on four plates and place the avocado halves on top.
Pour over the dressing and surround with the prawns.
Serve immediately.