Peppery braised broccoli rabe with arugula

Name: Peppery braised broccoli rabe with arugula
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Cuisine: European, Mediterranean
Ingredients: 1 bunch broccoli rabe; 1 small yellow onion, thinly sliced; 3 garlic cloves thinly sliced; Red pepper flakes; 4 oz arugula; 3 tablespoons pine nuts lightly toasted; 1/2 cup chicken stock; 1/4 cup olive oil