1/3 lb beef patties. Made with 100% angus beef. US inspected and passed by Department of Agriculture. boulderburgerco.com. Quality guaranteed: our commitment to quality is 100% satisfaction. Stack it. Build it. Top it off. Start with a Boulder Burger 100% angus beef patty and you've got yourself a burger that rocks. Meet the bacon & onion fiesta burger. Piled up high, this party on two patties gets high marks from us for its unexpected mix of mouthwatering ingredients! How bould is your burger? You've got the formula for burger excellence and you owe it to the world to share it. Visit the Boulder Burger Company Facebook page and tell use how you build your juiciest burger. Now so much the creative type? No problem! We're also sharing tons of recipes we know you'll love.