Petite Beef Wellingtons
For Large Version:
Prepare as above, except do not slice roast. Preheat oven to 425°F. Brown roast in the skillet 1 minute per side. Do not quarter pastry sheets. Overlap the 2 sheets by 1 inch. Roll the sheets together to an 18x15-inch rectangle. Spread mustard to an 8x6-inch rectangle in the center of the pastry. Top with mushroom mixture and cheese, then top with prosciutto-wrapped beef roast. Brush pastry edges with egg mixture then bring long sides over beef, pressing to seal. Fold up short sides. Place, seam side down, on the prepared baking sheet. Brush egg mixture over pastry. Arrange pastry strips as desired and brush with egg mixture. Bake for 45 minutes or until in instant-read thermometer registers 135°F. Let stand 5 minutes before serving. Serve with salad.
The 5 minute rest time will allow the internal temperature of the steaks to climb to about 145°F (medium).