1Preheat the oven to 160º C.
2Prepare the pâté de alheira: remove the skin from the alheira and place in a frying pan. Beat the egg with the chopped parsley and add to the alheira, stirring very well.
3Cut the loin as if it were unrolling, first making the cut leaving 1 cm in the bottom, until it reaches the middle and continue until opening the loin into a sheet.
4Fill with pâté, wrap carefully and tie with kitchen twine.
5Slice the onion, then peel and seed the tomato. Peel the garlic.
6In a baking dish place the onion, tomato, olive oil, wine, garlic, bay leaf and orange juice. Save a few slices of orange to put on top of the loin.
7Place the loin on the baking sheet, season to taste with salt and pepper. Top with the orange slices you reserved.
8Bake for 2 hours. Drizzle with the sauce in the middle of the baking.
9At the end of the time, remove the lid and raise the temperature to 220 ° for 10 minutes so the loin becomes golden.