Pork Tenderloin with Rosemary

Preheat oven to 450 degrees. In a small bowl, stir together 1 tablespoon butter, oil, garlic, rosemary, 1 teaspoon salt, and 1/4 teaspoon pepper.

In a small, shallow roasting pan, toss onions with half the butter mixture; push to sides; place pork in center. Rub remaining butter mixture over pork. Roast 10 minutes.

Heat broiler; set rack 4 inches from heat. Broil until pork registers 155 degrees on an instant-read thermometer, 10 minutes. Remove pork from pan.

Whisk flour and remaining 2 tablespoons butter in a small bowl; set aside. Place roasting pan with onions over medium-high heat. Add 3/4 cup water; bring to a boil, stirring to loosen any browned bits. Add Madeira and flour mixture. Cook sauce, stirring, until slightly thickened, 3 to 5 minutes.

Slice pork 1/4 inch thick, and divide among plates; spoon sauce on top.