To make things easy on the day, the white sauce in this recipe can be made one or two days in advance.

Ingredients

• ¼ small onion, sliced
• 1 small bay leaf
• 1 cup milk (preferably blue-top)
• 25 grams butter
• 2 tablespoons flour
• 50 grams gruyere cheese, grated
• 1 teaspoon grated lemon rind
• 1 tablspoon chopped fresh chives
• 4 large croissants
• 150-200 grams hot smoked salmon

Method

1. Heat together the sliced onion, bay leaf and milk to scalding point. Discard the onion and bay leaf.
2. Melt the butter in a heavy-based saucepan, then add the flour. Cook for 1-2 minutes over a moderate heat until bubbly, stirring regularly to prevent burning.
3. Remove from the heat and gradually stir in the infused milk to make a thin smooth sauce. Return to the heat and stir over a low heat until the sauce has thickened. Simmer for 2-3 minutes, stirring regularly. Add the gruyere cheese, lemon rind and chives, then remove from the heat and season with salt and white pepper.
4. Slice the croissants in half and spread a little white sauce in the middle of each. Divide the salmon among the croissants and cover with the remaining white sauce.
5. Re-heat in a 190ºC oven for 8-10 minutes until crisp and golden.