Festival food—made from the best of Borough Market’s seasonal produce—to turn a street party into a culinary triumph
1 egg yolk
1 tsp Dijon mustard
Sea salt and freshly ground pepper
300g crab meat, brown and white, kept separately
1 tbsp wholegrain mustard
2 tsp hot pepper sauce
100g butter, at room temperature for spreading
10 slices of bread, brown or white, whichever you prefer
First, make some mayonnaise. Place the egg yolk in a mixing bowl. Add in the mustard and whisk to combine. Ideally, you will need someone to hold the bowl for you, or else a tea towel to secure it.
Start pouring the oil into the egg yolk mixture in a thin stream, whisking vigorously all the while. Everything will start to emulsify and begin to look thick. If the mayonnaise splits while you are pouring in the oil, don’t waste it—just start the process afresh in a clean bowl with another egg yolk and a spoon of Dijon, then start adding the curdled mayonnaise as you would have done with the oil. You can of course use a hand whisk or even a plastic blade in a food processor to do the job.
When all of the oil has gone in, squeeze in the juice of half a lemon and also 1 tbsp cold water. Season the mayonnaise generously, tasting it to make sure it is not too oily. If it is, add a little more lemon.
Gently stir the brown crab meat into the mayonnaise, along with the whole grain mustard, pepper sauce and another good squeeze of lemon.
Butter the bread then top with the brown crab meat mixture, spreading it to cover the bread. Top each with some watercress, then scatter on the white crab meat.
Place on a large serving plate and decorate with the remaining lemons, cut into generous wedges.
Recipe: Lesley Holdship
Image: John Holdship