To make the marinade

1. Combine the mustard, lemon juice, garlic, black pepper and olive oil in a jar. Screw on the lid and shake well to combine. Alternatively, place the mustard, lemon juice, garlic and black pepper in a small bowl and whisk together. Stream in the olive oil, whisking until fully incorporated. Pour half of the mixture into a re-sealable bag and add the pepper, zucchini, squash and red onion. Cover the remaining marinade and refrigerate. Re-seal the bag and massage marinade into vegetables. Place in the refrigerator and marinate for at least 30 minutes and up to 2 hours.

To cook the quinoa

1. Place quinoa and water in a saucepan and bring to a boil over medium-high heat. Season with salt and reduce heat to a simmer and cook, uncovered for about 15 minutes. Drain off any excess liquid. Set aside.

To grill the vegetables

1. Preheat grill to medium high heat. Clean grill grates and brush lightly with vegetable oil. Remove the vegetables from the bag. Place the vegetables on the grill and cook vegetables on both sides until grill marks form, about 5-10 minutes per side. Remove from the grill.

To make the dish

1. Transfer the quinoa to a large bowl and toss with the reserved marinade. Chop the grilled vegetables and add to the quinoa, along with the lemon zest, chickpeas and basil. Stir and serve.