Preheat your oven to 425°F. While the oven heats, trim the green beans and asparagus: cut the green beans into 2-inch pieces and remove the woody ends from the asparagus, then cut the stalks to match the length of the green beans. Zest the lemon and finely snip the chives into 1/8-inch pieces. Juice the lemon and set the juice aside. Cut the chicken breasts into 1-inch chunks for even cooking.

In a small bowl, mix together the harissa spice blend, 2 tablespoons olive oil, and 1.5 teaspoons salt to create a paste. Add the chicken chunks to the bowl and toss until evenly coated with the spice mixture. Spread the chicken on a baking sheet in a single layer and place in the preheated oven. Roast for 12-15 minutes until the chicken is cooked through.

On a separate baking sheet, toss the trimmed green beans and asparagus from Step 1 with 2 tablespoons olive oil, salt, and pepper. Spread them in an even layer. When the chicken has been roasting for about 4-5 minutes, add the vegetable tray to the oven alongside the chicken. I find that starting the vegetables a bit later ensures they cook perfectly tender with a slight char while the chicken finishes. Roast the vegetables for 8-10 minutes until tender-crisp and lightly caramelized.

While the chicken and vegetables roast, combine the sour cream, reserved lemon juice, and most of the chives from Step 1 in a bowl, whisking until smooth and well combined. Season the sauce with salt and pepper to taste. This bright, creamy sauce will provide a cooling contrast to the warm harissa-spiced chicken.

When the chicken and vegetables are done cooking, transfer the roasted vegetables to a serving platter or bowl. Stir the lemon zest from Step 1 into the warm roasted vegetables, tossing gently to distribute. Arrange the roasted chicken alongside the vegetables. Drizzle or dollop the lemon-sour cream sauce from Step 4 over the chicken and vegetables, garnish with the remaining snipped chives, and serve with fresh lemon wedges on the side.