In a small saucepan, combine quinoa and broth and bring to a boil over high heat. Lower heat and simmer uncovered for 20 to 25 minutes, or until all liquid is absorbed.

Remove from heat and place broccoli on top of quinoa. Cover pot and let steam for about 10 minutes.

Meanwhile, in a small bowl, whisk together lemon juice, vinegar, garlic, oil, salt, and pepper until emulsified. Pour on top of broccoli and quinoa. Add herbs, feta cheese, and arugula (if using), and fluff with a fork.