It is very important that the cucumbers and capers are really dry. I even squeeze out the capers a bit. Otherwise the cream will be too runny.
With the blender: Roughly dice all ingredients, otherwise it may not make it.
With the food processor: just throw everything in and mix until everything is pureed. Then chill and make sandwiches afterwards.
Examples of using the cream:
The topping is either boiled ham or cold chicken or pieces of tuna or hard-boiled eggs or
Butter a slice of sandwich or white bread, put a lettuce leaf on it, a tablespoon of the cream, the topping (see above) a little more cream, a leaf of lettuce and then another lightly buttered slice of white bread. Wrap tightly in cling film and cool a little. They taste best when chilled. Very good to prepare as school bread.
Or you fill the cream into hollowed out tomatoes or onions, also on crackers, as a dip, in egg halves