Combine the sausage meat, breadcrumbs, milk, grated onion, salt, black pepper, thyme, sage, parsley, nutmeg, white pepper, and egg yolk in a food processor until smooth. The texture should be soft, almost like a paste. Cover and chill for 30 minutes.
Preheat the oven to 400°F (200°C). Line a large baking sheet with parchment paper.
Roll out the puff pastry on a lightly floured surface into a rectangle about 10x16 inches. Position it so the long side faces you.
Spoon the sausage mixture in a thick, even log along one long edge of the pastry, leaving about 1½ inches from the edge.
Fold the pastry over the filling and continue rolling until the seam meets the opposite edge. Trim any excess so there’s just one layer of pastry around the sausage. Seal the seam and brush lightly with beaten egg.
Using a sharp knife or kitchen scissors, make deep cuts every 1 to 1½ inches. ***See step by step photos up above.*ng.
Transfer the sausage roll to the prepared baking sheet, shaping it into a circle. Press the ends together firmly to form a ring. Twist each section slightly outward so the filling faces up.
Brush the entire wreath with beaten egg and sprinkle with sesame or poppy seeds.
Bake for 30–35 minutes, until puffed and golden brown and the sausage is cooked through. If it browns too quickly, loosely cover with foil for the last 10 minutes.
Cool slightly before transferring to a serving platter. Place cranberry sauce in the center.