First, preheat your oven to 400°F (204°C).
While the oven is preheating, peel and chop the beets into ½in (1.3cm) cubes. Then, rinse, remove the green top, and halve or quarter the strawberries. Separately, toss each ingredient in ½tbsp (7.5ml or 7g) of olive oil, sprinkle with ¼tsp (.6g) kosher salt, and transfer them to individual 3x18in (33x45.5cm) baking trays. Bake the beets for 45 minutes, or until a fork can pierce through the cubes with minimal resistance and bake the strawberries for 20 minutes.
While those are roasting, slice your nectarines and goat cheese. Then, get your arugula and white balsamic vinegar ready.
When finished, turn the oven down to 300°F (149°C) and add all of the strawberries (juices included) and half the beets to a blender and blend. Then add in the rest of the beets and blend again to finish the pureé.
Spoon the purée onto the flatbreads and spread it like you would a pizza sauce. Then place a layer of arugula (rocket) on top of the purée and add a layer of goat cheese and nectarines to the greens. Bake the flatbreads until the cheese softens, about 7-10 minutes.
Take the flatbreads out of the oven and drizzle with white balsamic. Then, slice, serve, and enjoy.