lemony broccoli-chickpea bowls

0 Heat the oven to 350°F. Toast the walnuts on a baking sheet until browned and fragrant, 7 to 8 minutes. Transfer to a bowl or cutting board. Increase the oven temperature to 425°F. 
1 Meanwhile, cut the broccoli into bite-size florets. Trim off the tough parts of the stem; discard. Slice the stem crosswise into 1/4-inch pieces. 
6 Drain the chickpeas in a colander but do not rinse. Arrange a few paper towels on the now-empty baking sheet (careful, it will be hot), then pour the chickpeas over top. Blot dry; discard the paper towels.
2 Add the broccoli florets and stems to the baking sheet. Drizzle everything with 2 tablespoons of  oil and season with salt and black pepper. Toss to coat, then spread in a single layer. Roast, tossing halfway through, until crispy, 25 to 30 minutes.
3 Meanwhile, cook the couscous according to package directions.
7 Make the pesto: in a small bowl, combine the basil, garlic, red pepper flakes, zest and juice of 1 lemon, and remaining 1 tablespoon oil. Chop the toasted walnuts and add half. Stir to combine. Taste and season with salt and pepper. 
4 Add the broccoli, chickpeas, capers, remaining walnuts, and half the sauce to the couscous. Stir to combine.
5 Divide the mixture between bowls and top with Parmesan and the remaining sauce, as desired.