Before starting, preheat the oven to 450˚F.Wash and dry all produce. Heat a large non-stick pan over medium-high heat. Meanwhile, peel, then cut half the onion (whole onion for 4 ppl) into 1/4-inch pieces. When the pan is hot, add 1/2 tbsp (1 tbsp) oil, then onions and sausage. Cook, breaking up sausage into smaller pieces, until no pink remains, 4-5 min.\*\* Carefully drain and discard excess fat.Season with garlic powder, salt and pepper. Cook, stirring often, until fragrant, 30 sec.

Meanwhile, halve tomato lengthwise. Thinly slice half the tomato into half-moons, then cut remaining tomato into 1/2-inch pieces.Arrange flatbreads on a parchment-lined baking sheet. (NOTE: For 4 ppl, use 2 parchment-lined baking sheets.) Spread pesto over flatbreads. (TIP: Skim off excess oil on top of pesto, if desired.)

Sprinkle half the mozzarella over flatbreads, then top with sausage-onion mixture.Top with sliced tomatoes, then sprinkle with remaining mozzarella and Parmesan.Bake assembled flatbreads in the bottom of the oven, moving to the top of the oven halfway through, until edges are golden-brown, 8-10 min. (NOTE: For 4 ppl, bake in the bottom and top of the oven, rotating sheets halfway through.)

Add half the balsamic glaze and 1 tbsp (2 tbsp) oil to a large bowl. Season with salt and pepper, then whisk to combine.

Add remaining tomatoes, croutons and spring mix to the large bowl with vinaigrette, then toss to coat.

Cut flatbreads in half. Divide flatbreads and salad between plates. Drizzle remaining balsamic glaze over flatbreads.