Before starting, preheat the broiler to high.Wash and dry all produce. Zest, then juice half the lemon (whole lemon for 4 ppl). Cut any remaining lemon into wedges. Cut or tear ciabatta into 1/2-inch pieces. Cut tomato into 1/2-inch pieces.

Heat a large non-stick pan over medium heat.While the pan heats, add ciabatta, half the garlic salt and 1 tbsp (2 tbsp) oil to a medium bowl. Season with pepper, then toss to coat.When the pan is hot, add ciabatta to the dry pan. Cook, stirring occasionally, until golden-brown on all sides, 3-4 min.Transfer croutons to a plate to cool.

Add breadcrumbs to a shallow dish. Pat chicken dry with paper towels. Carefully slice into the centre of each chicken breast, parallel to the cutting board, leaving 1/2 inch intact on the other end. Open up chicken like a book. Add chicken, mayo, lemon zest and remaining garlic salt to the same medium bowl (from step 2). Season with pepper, then toss to coat. Working with one chicken breast at a time, press both sides into breadcrumbs to coat completely.

Reheat the same pan (from step 2) over medium-high. When hot, add 2 tbsp oil, then chicken. Pan-fry on one side until golden-brown, 4-5 min. Flip chicken and add 1 tbsp oil. Pan-fry until golden brown, 4-5 min. (NOTE: Don't overcrowd the pan. Cook in batches for 4 ppl, using 3 tbsp oil per batch.) Transfer chicken to a foil-lined baking sheet. Sprinkle Parmesan over chicken. Broil in the middle of the oven until cheese is golden and chicken is cooked through, 2-3 min.**

Meanwhile, add lemon juice, 1/4 tsp (1/2 tsp) sugar and 1 tbsp (2 tbsp) oil to a large bowl. Season with salt and pepper, then whisk to combine.Add tomatoes, croutons and spinach, then toss to combine.

Thinly slice chicken. Divide chicken and salad between plates. Squeeze a lemon wedge over top, if desired.