Prepare 2 avocados, cut into small pieces and put in a high-sided container. Drizzle with 2 tablespoons lemon juice, add 2 g vitamin C if possible, salt and pepper.
9: Dip the unbuttered side into the beaten egg and leave to soak for 5 minutes.
10: Put a small frying pan on medium heat and add the bread fingers buttered side downwards. Leave to brown for about 5 minutes, then flip them and over and turn off the heat. Leave the eggy side to cook gently.
11: Just before serving, stick a bread finger or two into the mousse and garnish with a sorrel leaf. Serve without delay.
Remarks
You can use lime juice instead of lemon. In this case, reduce the quantity by half, as the flavour is much stronger. If you prepare this the day before serving, do add the Vitamin C and refrigerate covered with plastic film. Only transfer to the final individual glasses next day. The quantity of sorrel is for guidance, so use more if you like it.