1. To butterfly the chicken blot it dry with a paper towel. Place the chicken breast side down on a chopping board and use a sharp knife or scissors to cut along both sides of the backbone. (Discard the backbone or use it for stock). Using a sharp knife make a notch in the white cartilage at the neck and two slits on either side of the cartilage on the breast bone. Pop the breast bone out and remove.
2. Turn chicken over, open it like a book and press to flatten. Season with salt and pepper. Add it to a large ziplock bag with buttermilk and pickle juice. Remove the air from the bag then marinate in the fridge for 12–24 hours (overnight is easiest). 
3. Preheat the oven to 200°C. Remove chicken from marinade and allow it to come to room temperature. Place skin side up in a roasting dish.
4. Line a baking tray with baking paper. Add prepared garlic, eggplant, courgette, tomatoes and thyme. Drizzle with oil and season well. 
5. Place chicken and vegetables in the oven. After 40 minutes, check on the vegetables (the garlic and courgette may cook quickly), add asparagus and bake for another 10 minutes, until the chicken juices run clear and the vegetables are deliciously cooked.
6. Serve chicken with roasted summer vegetables, fresh basil and bread. 

*If you don’t have leftover pickle juice available then simply omit this and use 2 cups of buttermilk (instead of 1).