Choose small red onions for roasting as you really want the finished leaves to be bite-sized. The smoked eel can be replaced with smoked salmon or mackerel.
Makes: Approximately 20 pieces or bites
- 4 small red onions
- 1 tablespoon olive oil
- sea salt and freshly cracked black pepper
- 250g (9oz) smoked eel cut into dice or thin slices
- 5 tablespoons horseradish mayonnaise (see recipe)
- sprigs of chervil or watercress for garnish
- 2 egg yolks
- 2 tablespoons of Dijon mustard
- 1 tablespoon of caster sugar
- 2 tablespoons of wine vinegar
- 150ml sunflower oil or light olive oil or a mixture of both oils
- 1 heaped tablespoon of finely, grated fresh horseradish
- 1 teaspoon of chopped tarragon
- Preheat oven to 200°C/400°F/Gas Mark 4.
- Cut the unpeeled onions in half straight down through the middle and through the root. Brush the cut surfaces with olive oil and place cut side down on a roasting tray.
- Cook for 20-40 minutes or until the onions feel completely tender. Remove from the oven and allow to cool.
- When the onions are cool, separate the layers of onion to achieve little cup-shaped leaves. These can be prepared in advance and stored at room temperature.
- To assemble, place the onion leaves on a serving dish. Spoon a little of the horseradish mayonnaise into the base of each leaf and follow with a piece of eel and a spring if chervil or watercress.
- Put the egg yolks, mustard, sugar and vinegar in a bowl. Whisk well and add the oil gradually in a slow and steady stream while whisking all the time. The sauce will emulsify and thicken quite easily.
- Add the horseradish and chopped herbs. Taste and correct seasoning. It is unlikely to need salt because of the large quantity of mustard.
- Chill until needed.