Cucumber sandwiches are the quintessential expression of the old-fashioned tea sandwich. These are delicate little mouthfuls, prepared on thinly-sliced bread and offered up in the English fashion as a light meal with tea. Cookbooks dating from the early 1950s and before often give several pages to these sandwiches, cut very small and served on artfully-arranged trays. They can be made ahead of time, but there are limitations to their useful life.
Preparing cucumber sandwiches ahead of time is a delicate balancing act between the needs of the bread and the needs of the cucumber. The cucumber is a very watery vegetable, and over time it makes the bread soggy. If the sandwiches are held at room temperature, the cucumbers will soften after a few hours, losing the appealing contrast between the crisp vegetable and soft bread. Yet, if the sandwiches are refrigerated, the bread dries out and the sandwich has a stale flavour. Overnight refrigeration, then, is out of the question.
Preparing the Cucumbers
Cucumber sandwiches can be reasonably made ahead of time in the morning of the day they're to be served. Peel a section of English cucumber, or score the skin to make a pattern of green stripes. Slice the cucumber as thin as you possibly can, either by hand or on a slicer. Spread the slices on paper towels and salt them lightly, to draw out as much moisture as possible. After 30 minutes, rinse the slices with cold water and pat them dry on paper towels.
Preparing the Bread
Cucumber sandwiches are best made on a thinly-sliced Pullman, or sandwich, loaf. To provide a moisture barrier against the cucumbers, spread each slice with butter or cream cheese, or other similar mixture as directed in your recipe. This protects the bread from becoming soggy, and provides an additional richness and moisture in the mouth. Many recipes call egg salad, anchovy paste, Marmite, watercress or other ingredients. For advance preparation, quickly-perishable ingredients such as watercress should be avoided. The remainder holds up well enough under a few hours of refrigeration.
Assembling and Holding the Sandwiches
Prepare the sandwiches by laying out the buttered bread and layering it with cucumber slices. Season lightly with salt and pepper, and cover with another slice of bread. Cut away the crusts, and slice the sandwiches into small triangles or rectangles. The sandwiches maintain their quality under refrigeration for six to 10 hours, if layered on a sheet pan and covered closely with cling film. If you must make up the sandwich serving trays in advance, more surface area is exposed and they will dry out if held for more than four hours.