Start by slicing up the onions thinly. Once the they are prepared, add olive oil and plant-based butter to a large saucepan. Add a big pinch of salt and then cook the onions low and slow for as long as you can – up to about half an hour. This will build the savoury depth that will carry the dish.
Once the onions have really softened, add the chopped chestnuts, fresh sage and finely chopped garlic. Give the mixture a good stir and cook it down again for another 15 minutes until it is sticky and deeply brown. Add the miso paste, nutritional yeast, mustard, breadcrumbs and fennel seeds. Check the seasoning and stir well, then set aside.
Preheat the oven to 200˚C (180˚C fan)/390˚F (350˚F fan)/gas mark 6 (gas mark 5 fan).
Dust your work surface with plain flour and roll the puff pastry out into a large rectangle until it is half a centimetre thick. Add a thin layer of cranberry sauce down the middle of the rectangle before spreading the cooled sage and onion filling on top in an even log shape.
Fold one side of the puff pastry over the top of the log, and then roll the whole log towards the edge of the rectangle, so it’s wrapped up like tightly like a sausage. Brush the edges with a mixture of oat milk and maple syrup, so that they stick.
Gently lift the giant log onto a lined baking sheet then curl it into a circle shape so that the two ends are joined and it forms a wreath. With a sharp knife, cut 8 2-3 inch slits around the wreath so that the steam can escape during cooking and it gets nice and crispy. Finally, sprinkle with black and white sesame seeds, brush generously with the oat milk and maple syrup mixture and bake for 45 minutes until it’s gloriously golden.
Serve the wreath alongside festive sides such as crunchy Brussel’s sprout slaw, roasted carrots, extra cranberry sauce, roast potatoes and veggie gravy. It makes great leftovers sliced up and served cold as part of a Boxing Day buffet too.