Pork wellington

Name: Pork wellington
Ingredients: olive oil for frying; 2 large pork fillets (approx 800g), trimmed and the ends removed; 1 shallot finely chopped; 50g butter; 150g wild mushrooms (such as chanterelles), finely chopped; handful sage picked and chopped; handful parsley chopped; good handful chives snipped; 100g spinach; 10 slices prosciutto; 50g good-quality chicken liver pâté; 500g pack puff pastry; plain flour for dusting; 2 egg yolks beaten with 1 tsp water; 300ml pot double cream; 3 tbsp Dijon mustard