Start this recipe by heating the olive oil in a pan and sauté the onion and garlic together for 5 minutes until soft. Add this mixture to the pork mince along with 1 tbsp whole grain mustard, chopped sage and the dried bread crumbs. Season well with salt and pepper. Roll out the puff pastry and brush all over with half of the beaten egg. Next, place half of the pork filling onto one side of the pastry and flatten out to a rectangle. Leave a 2cm gap all around. Next, mix together the chopped apple and remaining 1 tbsp whole grain mustard and place in a line in the center of the pork mixture. Next, lay the remaining pork filling on top and flatten down on the sides to create a hump. Fold over the remaining puff pastry and seal together all the edges to create a parcel. Place onto a baking sheet with non-stick paper. Brush with the remaining beaten egg and bake in the oven at 160`c for 40-45 minutes or until cooked through.