Beef Wellington

Bahan-bahan (2 porsi)

• 10 ounces mushrooms (white or brown)
• 2 filet mignons (1 ½ inches thick)
• ½ teaspoon kosher salt (divided)
• ¼ teaspoon black pepper
• 1 tablespoon vegetable oil
• 1 tablespoon butter
• 2 tablespoons finely diced shallot
• 1 clove garlic (minced)
• ⅛ teaspoon dried thyme leaves
• 1 tablespoon cooking sherry
• 4 slices prosciutto
• 2 teaspoons Dijon mustard
• 1 sheet puff pastry (thawed)
• 1 large egg (lightly beaten)