Blend pesto ingredients except oil in a food processor then gradually add oil to form a paste.
Char peppers over a gas flame until black and steam in a covered bowl to peel and seed.
Coat chicken strips in oil and seasoning in a bowl.
Grill chicken, red onion, and courgettes on a hot griddle pan for 2 to 3 minutes.
Cut the top off the loaf and hollow it out leaving 3cm of bread around the edges.
Layer peppers, chicken, onion, courgette, mozzarella, tomato, and pesto inside the loaf with seasoning.
Replace the lid and press down firmly to set the loaf.
Whisk oil, vinegar, and mustard together then toss with salad leaves.
Slice the loaf and serve on plates with the dressed salad.