Before starting, preheat the oven to 450°F.Wash and dry all produce. Halve tomatoes. Core, then cut pepper into 1/4-inch pieces. Toss half the peppers with half the Italian seasoning in a medium bowl. Season with salt and pepper. Set aside.

Pat chicken dry with paper towels. Carefully slice into centre of each chicken breast, lengthwise and parallel to the cutting board, leaving 1/2-inch intact on the other end. Open up chicken like a book. Season both sides with salt and pepper, then sprinkle with remaining Italian seasoning.

Heat a large non-stick pan over medium-high heat. When hot, add 1/2 tbsp oil (dbl for 4 ppl), then chicken. Pan-sear, until golden-brown, 1-2 min per side. Remove pan from heat. Transfer chicken a parchment-lined baking sheet. Spread marinara over tops of chicken, then sprinkle seasoned peppers (from the medium bowl) and cheese over marinara. Roast in the middle of the oven, until chicken is cooked through, 12-14 min.\*\*

While chicken roasts, whisk together vinegar and 1 tbsp oil (dbl for 4ppl) in a large bowl. Add tomatoes, remaining peppers and arugula-spinach blend. Toss to combine. Season with salt and pepper.

Divide chicken and salad between plates.