Due to the nature of puff pastry, please follow these guidelines: Store in the freezer. Thaw in the refrigerator for 8-12 hours before use.Before starting, preheat the oven to 425˚F.Wash and dry all produce. Line a baking sheet with parchment paper.Unroll pastry on prepared baking sheet, discarding the wax paper. (NOTE: For 4 ppl, use 2 parchment-lined baking sheets.)Use a paring knife to score a 1/2-inch border around pastry. (NOTE: Make sure not to cut all the way through!)To prevent over-puffing, use a fork to prick inner tart 8-10 times, about 2 inches apart.

Season tart with salt and pepper, then bake in the middle of the oven until pastry is golden-brown and cooked through, 20-24 min. (NOTE: For 4 ppl, bake tarts in the middle and top of the oven, rotating sheets halfway through.)Meanwhile, halve tomatoes.Cut four sections off nectarine, avoiding the pit.Cut each section into 1/4-inch slices.

Add tomatoes, 1/8 tsp (1/4 tsp) sugar and 1/2 tbsp (1 tbsp) oil to an unlined baking sheet. Season with salt and pepper, then toss to coat.Arrange tomatoes, cut-sides up. Roast in the bottom of the oven until tender and lightly golden, 7-10 min.

Meanwhile, add vinegar, 1/4 tsp (1/2 tsp) sugar and 1 tbsp (2 tbsp) oil to a large bowl. Season with salt and pepper, then stir to combine.Cut or tear mozzarella into 1/2-inch pieces.Season mozzarella with salt and pepper right on the cutting board. (TIP: Tearing the mozzarella into rustic 1/2-inch pieces creates perfect nooks and crannies to season!)Combine mayo and half the pesto in a small bowl.

Once tart is out of the oven, allow to cool for 3-4 min.Spread pesto-mayo over tart. Top with mozzarella cheese and roasted tomatoes.Drizzle remaining pesto over top.

Cut tart into quarters.Add arugula and spinach mix and nectarines to bowl with dressing. Toss to coat.Divide tarts and salad between plates.