Pre-heat the oven to 190C, 375F, Gas mark 5. Drain the can of salmon and make the juice up to 150ml / 1/4 pint with water for fish stock. Break the salmon into large chunks and arrange it with the broccoli in a single or 4 individual ovenproof dishes. Put the fish stock, wine, parsley and cornflower into a saucepan and blend until smooth. Heat gently, stirring all the time until the sauce thickens. Pour over the salmon and broccoli. Arrange the slices of cheese over the top of the dish and bake for 20 minutes or until the cheese has melted. Serve immediately. Serves 4. Approx. 395 kcals per serving