Round Roast with a pistachio-leek pesto becomes an affordable meal for weeknight or a special occasion.
Preheat oven to 325°F . Heat medium nonstick skillet over medium heat until hot; coat with cooking spray. Add leeks; cook 10 to 15 minutes until leeks are caramelized, stirring often. Set aside to cool.
Season roast with 1-3/4 teaspoon salt and pepper.
To prepare pesto, add leeks, basil, thyme, parsley, shallots, garlic and 1/4 cup pistachios to food processor container. Cover; process until smooth, scraping sides as needed. While food processor is running, add oil and remaining 1/4 teaspoon salt; process until blended, about 1 minute. Reserve 1/4 cup pesto mixture; cover and set aside. Add balsamic vinegar to food processor. Cover; process until smooth. Cover and set aside.
Spread reserved 1/4 cup pesto over seasoned roast. Place roast, fat-side up, on rack in shallow roasting pan. Insert ovenproof meat thermometer so tip is centered in thickest part of beef, not resting in fat. Do not add water or cover. Roast in 325°F oven 1-1/4 to 1-3/4 hours for medium rare doneness.
Remove roast when meat thermometer registers 135°F for medium rare doneness. Transfer roast to carving board; tent loosely with aluminum foil. Let stand 15 to 20 minutes. (Temperature will continue to rise about 10°F to reach 145°F for medium rare.)
Carve roast into slices; top with pesto and remaining 1/4 cup pistachios, as desired.