INGREDIENTS
1 lb
beef sirloin, top round london broil, or leftover roast beef
2 cups
thickly sliced fresh mushrooms
1 cup
pearl onions
2 tbsp
butter
1/2 tsp
thyme
1/2 tsp
pepper
1 1/2 cups
beef (brown) gravy*
1
sheet frozen puff pastry, thawed
1
egg, beaten