I cannot remember exactly where I saw this first but I do recall a 60’s looking book with a sun bleached dust jacket and the weirdest coloured food inside. This is ingenious and thought it should resurface. You will need a good large crusty bloomer loaf not the pale soft and weedy type that people give to one footed pigeons.
For the mayonnaise
Place the loaf on its side on a board and carefully slice off the top. Keep it to one side. Upright the loaf again. With a knife about 1 inch from the from the outside cut into the soft bread down all four sides. With your fingers pull the dough from inside. Put the dough to one side and leave to dry. Later you can put it in a food processor and make into crumbs. They can be frozen for another day.
To make the mayonnaise, put the egg yolks, mustard, a good pinch of salt and the vinegar in a jug and blend with a stick blender until well combined. If you don’t have a stick blender, a small food processor will also do the job.
Slowly add the oil, blending continuously until the mayonnaise thickens and becomes smooth and glossy. Add ground black pepper and salt to taste. Spoon into a small jam jar and fasten the lid.
Put the jar inside the loaf of bread and add the hard-boiled eggs. Scrub the vegetables and cut into small batons where necessary. Arrange alongside the mayonnaise and eggs inside the loaf. Wrap some sea salt and ground black pepper individually in small envelopes of foil and add to the parcel.
Pop the lid back on and secure with a large elastic band or some good string then disappear on your picnic from whence you will return with only the empty jar elastic band and foil.
I guarantee your friends will be amazed by this novelty loaf.