Artichoke, melted onion and brie tart

Method

1. Heat the butter in a large, lidded heavy-based frying pan over a low-medium heat and fry the onions, garlic and most of the thyme with a pinch of salt and pepper. Put the lid on and cook for 1 hour (check now and then). Drain in a colander and remove any woody thyme sprigs.
2. Bring a large, lidded pan of water to the boil and cook the regular artichoke for 10-15 minutes with the lid on until the thickest part of the stem is tender (push a cocktail stick into the base of the artichoke to check). Cook the baby artichokes for 5-10 minutes until tender, then drain.
3. When cool enough to handle, slice off and discard the top third of the regular globe artichoke and trim any tough stalk. Pull off all the dark outer leaves to expose the soft lighter ones. Quarter the regular artichoke and halve the baby ones lengthways. Remove the spiky hairs from the middle using a teaspoon. (Baby artichokes may not have these but check and pull out any purple spikes.) Put the prepared artichokes into acidulated water as you work (see Know-how).
4. Heat the oven to 200°C/180°C fan/gas 6. Roll out the pastry on a lightly floured surface to a 30cm round, transfer to a lightly floured baking sheet, prick all over with a fork, then brush with the beaten egg. Bake for 
15 minutes until golden and puffed.
5. For the vinaigrette, boil the meat juices/gravy for 1-2 minutes, then remove from the heat and mix with the olive oil, mustard and vinegar. Taste and season if needed.
6. Press the pastry down using 
a spatula. Spoon the onions on top, then scatter with the artichokes. Tear the brie into chunks and scatter over the tart. Bake for 10 minutes to melt the cheese. Tear and scatter over the remaining thyme and dress with the vinaigrette.