Wash and dry all produce. Adjust rack to upper position and preheat oven to 450 degrees. Halve squash lengthwise, then slice crosswise into thin half-moons. Trim, then thinly slice scallions. Halve lemon. Halve tomatoes lengthwise. Pick basil leaves from stems; discard stems.

Heat a large pan over medium heat. Add pine nuts and toast, tossing frequently, until golden brown and fragrant, 3-4 minutes. (TIP: If nuts seem like they might burn, remove pan from heat for a few seconds.) Remove nuts from pan and set aside.

Heat a drizzle of olive oil in same pan over medium-high heat. Add scallions and cook until fragrant, about 30 seconds. Add squash and cook until soft and lightly browned, 5-6 minutes, tossing. Season with salt and pepper.

Place flatbreads on a baking sheet. Tear mozzarella into small pieces with your hands and scatter over flatbreads. Top with squash mixture. Bake in oven until cheese is melted and flatbreads are golden brown, about 10 minutes.

Meanwhile, toss mixed greens, tomatoes, a squeeze of lemon, and a drizzle of olive oil in a medium bowl. Season with salt and pepper.

Once flatbreads are done, scatter with basil, pine nuts, and chili flakes (to taste). Drizzle with honey. Cut into slices and serve with salad on the side.