Budget-Friendly Chicken Wellington

Ingredients

• 12 oz cremini mushroom, stemmed and wiped clean
• 4 tablespoons extra virgin olive oil, divided
• ½ teaspoon garlic powder
• ½ teaspoon onion powder
• ½ teaspoon dried thyme
• 2 teaspoons dried parsley
• 1 ½ teaspoons kosher salt, divided
• ¾ teaspoon freshly ground black pepper, divided
• 1 boneless chicken breast, large
• 1 tablespoon dijon mustard
• 4 slices prosciutto
• 1 sheet frozen puff pastry, thawed
• large egg, beaten
• 1 tablespoon extra virgin olive oil
• 2 tablespoons all purpose flour
• 2 cups chicken stock
• ½ teaspoon kosher salt
• ¼ teaspoon ground black pepper