Egg Mayonnaise with Pea Shoots

When I lived in London I had a weakness for the egg mayonnaise sandwiches that were sold in the train station. Served on a soft roll, they were filled with sliced, hard-boiled eggs and tomatoes, and smeared with mayonnaise. I have always been a fan of traditional egg salad but there is something great about eating the egg sliced instead of chopped and mixed with the mayo. I had these wonderfully sweet pea shoots from the market and I thought they'd go well with egg, but this would also be good with watercress or baby lettuces.