1-2 pound pork loin roast
1 cup fresh mushrooms, chopped
1/4 cup onions, finely chopped
1 tablespoon butter
1 tablespoon lemon juice
1/2 teaspoon rosemary, crushed
1 egg yolk, beaten
1/3 cup Romano cheese, grated
1/4 cup walnuts, finely chopped
For the filling:
Stirring frequently, cook mushrooms and onion in butter over medium-low, in a medium saucepan, heat until tender and the liquid has evaporated.
Remove from heat, stir in lemon juice, rosemary, egg yolk, Romano and walnuts; set aside.
Butterfly pork loin by cutting through roast horizontally to within 1/4-inch of the other side. Do not cut all the way through. Open out and pound to roughly a 6×8-inch rectangle. Spread filling evenly on meat rectangle. Roll up lengthwise; tie with kitchen string at 1-2 inch intervals to secure.
Place roast in shallow pan and rost in a 350 degree F. oven for 20-40 minutes (20 minutes per pound) or until internal temperature on a thermometer reads 145 degrees F. Remove roast from oven; let rest about 10 minutes. Slice to serve, removing string.