Step 1 Lay 1 chicken fillet on a piece of cling film on a work surface; top with another piece of film. Beat fillet with a meat mallet or rolling pin until 1cm thick. Peel off cling film and discard. Top fillet with a quarter of the feta, 2 basil leaves and 1 tablespoon roast capsicum.
Step 2 Roll up fillet, from a long end, to enclose filling; tie with kitchen string at even intervals to secure. Repeat process with remaining chicken and filling ingredients to make 4 involtini.
Step 3 Oil a barbecue grill plate; set to medium heat. Cook chicken involtini and eggplant rounds in batches, turning occasionally, for 12 minutes, or until chicken is cooked through. Set involtini aside. Chop eggplant roughly.
Step 4 Combine eggplant with onion, baby rocket and olives in a large salad bowl. Add remaining feta and roast capsicum to bowl with extra basil leaves. Drizzle salad with balsamic vinegar and toss. Remove string from involtini and discard. Slice involtini thickly.
Step 5 Serve involtini with salad and torn wholegrain baguette.