Mix the soy sauce, sherry and honey, brush the fillet with it and marinate for 2-3 hours.
Preheat the oven to 240 degrees.
Strip the marinade off the fillet, brush with the olive oil, season with salt and pepper, place in an ovenproof dish and fry in the preheated oven on the second bottom shelf for 12 minutes.
Set the temperature back to 80 degrees, open the door until the temperature in the oven has dropped to 80 degrees. (An oven thermo helps here)
Cook the fillet at 80 degrees for 45 minutes.
Peel and core the apples, cut into slices and drizzle with lemon juice.
Heat the butter and sugar, add the apple slices, deglaze with 50 ml veal stock and sauté until translucent.
Reduce the rest of the veal stock with calvados down to half and stir in the double cream. Pull the butter in small pieces into the sauce.
Cut the finished fillet into slices, serve with the apple slices and the sauce.