You will need
1 x Sour Cream Pastry or 1 kg bought flaky pastry made with butter.
1 sheet of rice paper
1 egg, beaten with a pinch of salt and sugar
A frozen Wellington should be defrosted while well covered, to prevent condensation making the pastry soggy. Bake for a little longer as the internal temperature will be lower.
1. Slice butterfly steaks from fillet, flatten them slightly. Season on both sides with Garlic Pepper Seasoning and drizzle with olive oil. Turn to coat. Rest for 30 minutes at room temperature. Cook on a very hot griddle pan until nicely marked on the outside but still raw inside. Spread steaks out on a baking tray. Cool for 10 minutes.
Spread a generous layer of chicken liver paté over each steak. Sauté the mushrooms with butter and oil until just wilted. Season with Garlic Pepper Seasoning and add thyme and nutmeg. Sprinkle White Sauce Powder over and stir in. Leave to cool. Divide the mushrooms between the steaks and push lightly into the paté. Leave everything to cool down completely.
2. Roll the pastry out thinly into a large rectangle. Lift it up and lay on a length of baking paper that will fit onto your biggest oven pan. Cut the rice paper in half lengthways and lay overlapping strips of rice paper along the middle length. This will prevent soggy pastry when the steak is added. Overlap the prepared steaks on top of the rice paper on top of the pastry.
3. Cut slanted cuts into the pastry on both sides of the meat with a pizza wheel or knife.
4. Plait the pastry strips over the meat to cover it completely. If at all possible refrigerate until dinner time. Keep pastry on the baking paper. Alternately, if pre-preparing for much later, cover with a double layer of cling film and freeze for up to 3 months.
5. Adjust the oven rack to the middle position. Preheat oven to 200°C. Brush pastry with egg glaze. Place a large baking sheet in the oven to preheat it.
Slip the baking paper with pastry on, onto the preheated baking tray. Bake for ±30 minutes until nicely browned. Rest for 5-10 minutes. Transfer to a large rectangular carving board or serving platter. Slice across into neat portions for serving.