Fillet of venison and wild mushroom sauce

INGREDIENTS

• 500g/1lb 2oz venison
• 5 tbsp extra virgin olive oil
• 1 tbsp balsamic vinegar
• 1 carrot
• 1 onion
• salt and freshly ground black pepper
• 100g/3½oz unsalted butter
• 2 small onions
• 40g/1½oz dried morels
• 150g/5oz fresh porcini mushrooms
• 2 tbsp balsamic vinegar
• 4 tbsp dry sherry
• 6 tbsp double cream
• 1 summer truffle