Peel the shallot, chop finely and sweat in 1 tablespoon butter in a small saucepan until translucent. Add the wine and simmer for 2-3 minutes, until the liquid has evaporated. Set aside to cool.
Season the meat with salt and pepper. Melt the remaining butter in a large frying pan and sear the meat for about 2-3 minutes per side.
Slice the bread roll and spread the mayonnaise over the cut sides. Top the bottom bun with lettuce, beet and tomato. Add the meat, shallot and top bun and wrap in a napkin, if desired.