Add a layer of game paté before the mushrooms for a really rich recipe! You will need about 250g.
About 900g Venison fillet
2 tablespoons olive oil
30g unsalted butter
1 medium onion, very finely chopped
2-3 cloves garlic, finely chopped
350g decent mushrooms (dark open cap, chestnut, Portobello or wild), very finely chopped
2 teaspoon chopped fresh thyme
150ml double cream
500g ready-made puff pastry
1 egg, beaten
sea salt and freshly ground black pepper
Trim the fillet if needed, rub with olive oil and season with salt and freshly ground black pepper, then tie at regular intervals with string to keep the fillet nice and round in shape. Heat a large frying pan that will take the piece of venison until smoking-hot. Sear the fillet all over for about a minute or until nicely brown. Immediately remove to a cold tray, cool then refrigerate for 30 minutes.
To make the mushroom duxelles. Melt the butter in a frying pan and fry the onion and garlic until very soft but not browned.
Add the mushrooms and continue to cook for a further 2-3 minutes. Stir in the thyme and Madeira and boil fast until all the liquid evaporates. Stir in the cream and bubble until very thick. Season well with salt and freshly ground black pepper. Set aside to cool completely.
To assemble the Wellington, roll the pastry to a rectangle large enough to comfortably wrap around the venison. Lay the fillet in the centre and cut the corners off the pastry so that you don’t get a build up of too much pastry.
Lift off the venison and spoon the mushroom duxelles down the centre of the pastry. Set the fillet on top, pressing into the mushrooms.
Brush the edges of the pastry with beaten egg and bring up over the fillet to enclose the meat and mushrooms. Press the pastry well to seal. Trim off any excess pastry and turn the parcel seam-side down onto a buttered roasting tray. Add any pastry decorations at this stage. Chill in the fridge for 30 minutes.
Preheat the oven to 220C/425F/Gas 7.
Remove the venison from the fridge and brush the pastry all over with beaten egg. Bake for 20 (RARE) – 25 (MED RARE) minutes until golden. Remove from the oven, and leave to rest in a warm place for 5 -10 minutes before slicing to serve.