A watercress sandwich is an English sandwich or finger food that traditionally is served during an English high tea as part of a larger spread of foods. The most basic type of watercress sandwich has two pieces of crustless white bread with a mixture of butter and watercress greens spread inside. Variations of the classic sandwich include mixing the watercress with hardboiled or deviled eggs, using mayonnaise instead of butter, or adding cream cheese to the mixture. Although white bread is the most frequently used type of bread for the sandwich, pumpernickel or rye sometimes is used as a contrast to the color of the filling. Serving a watercress sandwich is as much about the taste of the sandwich as it is about the presentation, with many versions seeing the sandwich cut into small, sharp triangles that are stacked elegantly on a serving platter.
The basis for a traditional watercress sandwich is the filling. This is made by placing watercress, room temperature butter and some lemon juice together in a bowl and mixing them by hand or in a food processor until a smooth spread has formed. The spread also can have other ingredients — such as salt, pepper, curry powder or cumin — added. Other smooth ingredients, such as mayonnaise, Greek yogurt, cream cheese or sour cream, also can be combined with the watercress.
Once the spread has been made, it can be chilled until it is needed or it can be used right away. When used, watercress spread should be at room temperature. It is spread on the inside of a slice of bread in just enough of a quantity to hold the bread together.
The bread that is used for a watercress sandwich usually is plain or country white bread. The crust is cut from the bread both for presentation and to create a more consistent texture in the sandwich. After the spread is applied and the sandwich is closed, it usually is cut from one corner to the opposing corner to create four triangular pieces. Alternately, a round pastry cutter can be used to make small circular sandwiches. In some cases, especially if a more rustic loaf is used, the bread can be left intact as a whole sandwich.
Some variations of the classic watercress sandwich have made their way into English high tea services in their own right. These include a watercress and egg sandwich in which the watercress is mixed with mashed hardboiled eggs and mayonnaise, and watercress and cucumber sandwiches that are made with watercress, butter and cucumbers. More rarely, the sandwiches can include meats such as shredded oxtail or thin slices of roast beef.