Rinse the tomatoes, remove the stalks and cut into slices. Rinse the lettuce, drain well and pluck into smaller pieces, if necessary. Cut the beets into thin slices. Spread mustard on two slices of bread. Spread mayonnaise on the other two slices of bread.
Place the lettuce, tomatoes, turkey breast and beet on the slices of bread with mustard. Top with the bread slices with mayonnaise. Cut in half and serve.