Fish surprise

1. Place the fish fingers on a lightly oiled baking sheet. Grill 3 to 5 minutes on each side until they are nicely browned.
2. Heat the oil in a small saucepan (preferably non-stick) and fry the onions until they are soft and pale gold in colour.
3. Add the remaining ingredients and cook, stirring, over a low heat until thickened. The sauce should not be runny, but add a little water or milk if it thickens too much.
4. Cut foil into 4 x 30 cm squares and place, shiny side up, on a work surface.
5. Spread a good spoonful of sauce in the centre of each of the foil squares. Arrange 4 fish fingers on the sauce and top with another spoonful of sauce.
6. Make parcels by folding the foil over and sealing the edges well by crimping them together.
7. Place on a baking sheet and bake in a preheated 200 ºC oven for 10 minutes.
8. Serve each person a closed parcel accompanied by a hot or cold potato salad and a simple green salad.