How Do I Make Beef Wellington? My Easy &amp - Chef YoYo

Ingredients

• 2 lb (900 g) beef tenderloin, trimmed
• Salt and black pepper, to taste
• 2 tbsp (30 ml) olive oil
• 10 oz (300 g) cremini or button mushrooms, finely chopped
• 4 oz (115 g) prosciutto, thinly sliced
• 2 tbsp (30 g) Dijon mustard
• 1 sheet (about 14 oz/400 g) puff pastry, thawed
• 1 large egg, beaten (for egg wash)
• 2 tbsp (30 g) unsalted butter
• 2 cloves garlic, minced
• 2 shallots, finely chopped
• 1 tbsp (15 ml) fresh thyme leaves