Indulge in this luxury paté with a good bottle of red wine. You'll need to start this recipe a day ahead.
Combine goose legs and breasts, salt and half each of the orange rind, thyme and garlic in a non-reactive baking dish. Make sure goose is covered with salt. Cover with plastic wrap and refrigerate overnight.
Preheat oven to 130C. Remove goose from dish and rinse off excess salt. Pat dry with absorbent paper. Combine with pork belly, goose fat, ½ cup water and remaining orange rind, thyme and garlic in a casserole. Cover and roast until meat is falling from the bone (about 2 hours), then cool.
Using a slotted spoon, transfer meat to a tray. Remove skin and bones and discard. Reserve fat. Using 2 forks, shred meat as finely as possible. Transfer to a bowl, add quatre épices, Cognac and 1/3 cup of the reserved goose fat (remaining fat can be refrigerated for up to 1 month and used for confit or as oil or butter substitutes in cooking). Mix thoroughly to combine, then pack firmly into a 1½ litre-capacity terrine. Place butter in a heatproof bowl placed over a saucepan of simmering water and, when just melted, pour over rillettes to cover. Refrigerate until firm (about 2 hours). The rillettes will keep in the refrigerator for up to 2 weeks.
For pears in grape must, combine pears and saba in a saucepan and bring to the boil. Reduce heat to medium. Simmer until pears are glazed and syrup is thick (5-7 minutes).
Garnish rillettes with thyme sprigs and serve with toast and pears to the side.