1. Heat oven to 275°. Trim any large pieces of fat from the outside of pork (you can use this to create the 4 ounces pork fat if you like) and cut meat into about ½-inch cubes. Cut trimmed fat and any additional fat into small cubes. Place meat cubes and all fat in a heavy Dutch oven that holds at least 4 quarts. (If your meat has a bone, you can add that for slow cooking, then remove meat and discard bone.)
2. Add thyme, mace, salt and garlic along with the peppercorns and juniper and mix everything together. Add wine, place pot in center of oven and bake 3 hours. After 3 hours, taste a piece of pork and add salt and pepper if necessary.
3. If a lot of solid fat remains in the pot, continue cooking another hour. When fat has melted completely, empty contents into a large colander over a bowl and let fat drip through. Press meat gently to extract remaining fat. Leave drained fat to cool and transfer to fridge for 20 to 30 minutes to chill and solidify.
4. Use 2 forks or your fingers to shred meat, then pack lightly into glass jars or individual ramekins.
5. Remove chilled fat from the fridge. If any juices remain (they may have gelled), combine with meat. Gently melt fat and pour over rillettes, being sure to have a solid layer of fat over top to seal meat and keep moist. Let mixture cool to room temperature, cover and store rillettes in fridge until ready to serve. Mixture keeps for weeks (months, even) refrigerated and as long as top fat layer is not disturbed.
6. To serve, remove from fridge and let rillettes warm to room temperature. Serve with slices of crusty bread and pickles.

Serves 10 or more.