"This is a recipe that comes from lots of trying and tweaking. My husband and 4 children love this savory tender meat with the sweet sauce drizzled over it. It's elegant and pretty enough for a dinner party, but not a lot of work."
Melt 2 tablespoons butter in a skillet. Cook and stir mushrooms and garlic in melted butter until tender, about 3 minutes. Remove skillet from heat. Mix bread crumbs, blue cheese, pistachio nuts, cranberries, parsley, onion powder, and seasoned salt into the mushroom mixture.
Cut a long slice lengthwise down the center of the tenderloin to within 1/2 inch of the other side. Spoon stuffing into the slice and fold meat around the stuffing. Secure tenderloin closed with kitchen string. Brush olive oil over the tenderloin; sprinkle with salt. Put tenderloin in a roasting pan.
Roast in preheated oven until an instant-read thermometer reads 140 degrees F (60 degrees C), 35 to 40 minutes. Cover beef loosely with aluminum foil and rest meat 15 minutes before slicing.
As the beef roasts, stir currant jelly, Merlot wine, beef broth, and 2 tablespoons butter together in a saucepan; bring to a boil. Reduce heat to medium-low and cook at a simmer until thick and syrupy, 35 to 40 minutes.
Arrange beef slices onto a platter and drizzle with currant sauce to serve.