Toast quinoa, stirring, in nonstick skillet over medium-low heat, 5 minutes.

Bring broth and water to boil in medium saucepan; stir in quinoa. Reduce heat to medium-low; cover and simmer 12 to 15 minutes until liquid is absorbed and quinoa is tender. Fluff with fork and transfer to large bowl; cover and keep warm.

 Heat a small amount of water or broth in large nonstick skillet over medium-high heat. Add onion and garlic; cook 3 minutes. Stir in broccoli rabe, salt and red pepper. Cook until broccoli rabe is tender, 5 to 7 minutes. Stir vegetables into quinoa.

 Serve warm or at room temperature.