In a bowl combine the mayonnaise, crème fraîche, lemon juice and the salt and whisk to combine. Taste and adjust the seasonings if necessary.
In a second bowl, combine the green cabbage, carrot, shallot, fennel and lemon juice.
Peel, core and slice the apple into matchstick sized pieces and add to the bowl. Drizzle the dressing over and stir to combine. Leave for 15 -20 minutes to set in the fridge.
Slice the bread and build the sandwich with the turkey, stuffing and apple slaw.