Add tomatoes, cucumber, red pepper, onion and stale bread to a bowl. Add olive oil, apple cider vinegar and salt and mix to combine. Put the bowl in the fridge for 30 minutes to one hour (optional)
I like to do this if I have time because in this way the ingredients absorbs the flavours more, but you can skip this step.
Add the ingredients to a blender and blend until smooth, add some cold water if necessary (if it looks too thick). Serve and top with a drizzle of olive oil and some crunchy croutons.