Blue Cheese-Mushroom Stuffed Tenderloin

Directions

1. Preheat oven to 425°. In a small skillet, heat butter over medium-high heat. Add mushrooms and Worcestershire sauce; cook and stir until mushrooms are tender, 6-8 minutes. In a small bowl, mix mustard, pepper, oil and salt.
2. Cut lengthwise through the center of roast to within 1/2 in. of bottom. Open roast and cut lengthwise through the center of each half to within 1/2 in. of bottom. Open roast flat; cover with plastic wrap. Pound with a meat mallet to 3/4-in. thickness.
3. Remove plastic. Spread mushrooms down center of roast to within 1/2 in. of ends; top with 1/2 cup cheese and onions. Starting at a long side, roll up jelly-roll style; tie at 1-1/2-in. intervals with kitchen string. Secure ends with toothpicks.
4. Place on a rack in a shallow roasting pan; spread with mustard mixture. Roast until meat reaches desired doneness (for medium-rare, a thermometer should read 135°; medium, 140°; medium-well, 145°), 40-50 minutes.
5. Remove roast from oven; tent with foil. Let stand 15 minutes before slicing. Remove string and toothpicks. Top servings with remaining cheese. If desired, warm additional onions in microwave and sprinkle over tops.