In a large skillet over medium-high heat, heat the olive oil. Add the onion and cook, stirring occasionally, until translucent and soft, about 5 minutes. Add the beef and pork and cook, breaking it up with a spatula, until no longer pink, about 5 minutes. Drain off the excess fat and add the Asian BBQ sauce. Cook, stirring, for 1 minute. Add the beef broth and lower the heat. Cook, uncovered, stirring occasionally, until the sauce reduces, about 10 minutes.