Method 1. Preheat the oven to 220C/gas 7. Season the beef fillet. Heat the olive oil in a frying pan and sear the meat all over. Transfer to a roasting tray and bake in the hot oven for 5 minutes to give rare meat (cook a couple of minutes longer for medium-rare if preferred). Remove the beef from the oven, cover with foil and set aside to rest.
Reduce the oven temperature to 190C/gas 5. Halve the aubergine lengthways. Place it in the centre of a large piece of foil and sprinkle it with salt and the sugar. Fold the foil to give a package, crimping the edges to seal. Place it on a baking sheet and cook for 30 minutes, or until the flesh is soft. Remove the aubergine from the foil and set aside in a colander to drain and cool.
Heat the chorizo oil in a small frying pan, add the sliced shallots and fry gently until soft, without letting them brown. Drain off the excess oil and set the shallots aside to cool.
Halve the puff pastry. Roll out each piece to give a rectangle and cut off 2 long thin strips from each to use later for decoration.
Cut the pastry rectangles in half. Spread one half with sun-dried tomato paste, then place the second piece of pastry on top. Carefully roll each batch again to help the layers stick together. Cover and allow to rest in fridge.
Meanwhile, to make the anchoïade, combine all the ingredients in a small bowl and stir together.
Make sure that all the ingredients are cold before assembling the dish.
Place one of the puff pastry rectangles on a baking tray. Lay a crêpe over it, then place one aubergine half on top, skin-side down. Cover with half the shallots and place the beef fillet on top of them.
Repeat the process in reverse: covering the meat with shallots, aubergine (skin-side up) and the second crêpe. Tuck the edges of the crêpes in to form a neat package. Lay the second piece of pastry on top and pinch the edges together in the style of a Cornish pasty, all the way around the rim.
. Preheat the oven to 230C/gas 7.
. Mix the egg yolk together with a little olive oil to make an egg wash. Brush this mixture all over the pastry parcel. Take the reserved strips of pastry and arrange them on top of the parcel to form a Union Jack pattern.
. Insert a sprig of thyme into each corner (the thyme must be well-soaked in water to prevent burning. Place the pastry parcel on a baking tray and cook for 15 minutes. Then remove it from the oven for 10 minutes before baking it again for another 15 minutes to ensure the pastry stays crisp.
. Meanwhile, heat a little beef stock in a small saucepan and stir in the anchoïade.
. Remove the beef parcel from the oven and cut a small hole in the top. Carefully pour the stock and anchoïade mixture into it (use a small funnel if you have one, otherwise a lipped pan or heatproof jug).
. Carve the parcel into thick slices and serve with a mixture of spring vegetables, blanched then tossed in melted butter in a frying pan and seasoned to taste.