Bring a pan of water to the boil, add the eggs and set the timer for 9 mins.
Meanwhile, lightly butter each slice of brioche on one side and heat a griddle pan. Char the brioche on the hot pan until griddle
lines appear, then flip and char the other side. Place the bread in a toast rack or on a wire rack to cool.
When the egg timer goes off, put the eggs in cold water for 10 mins to cool. Peel, then mash the eggs with a little seasoning, and stir in the mayo. Chill the egg mayo and store the toasted bread in an airtight container until you’re ready to serve.
Just before serving, assemble the sandwiches, then cut off the crusts and cut each sandwich into 2 or 3 fingers. Pop a slice of crispy bacon into each finger, so it sticks out the ends a little, and serve straight away.