Prep and Preheat: Preheat your home oven to 425°F (220°C). For the absolute crispiest crust, place a pizza stone or baking steel on the center rack during the preheating process. Alternatively, line a sturdy, large rimmed baking sheet with a sheet of parchment paper.
Season the Base: Arrange your two pre-made flatbread bases side-by-side onto your prepared parchment-lined baking sheet or onto a floured pizza peel. Using a pastry brush, coat the entire top surface of each flatbread evenly with the extra virgin olive oil. Lightly scatter a tiny pinch of sea salt across the oiled surfaces.
Layer the Ingredients: Distribute your fresh blueberries evenly across both flatbreads. Using your thumb, gently press down on a few of the berries to anchor them firmly onto the dough. Scatter the paper-thin red onion half-moons and the finely chopped fresh rosemary over the berries. Generously dot the entire surface with your crumbled room-temperature goat cheese, ensuring excellent distribution.
Bake to Golden Perfection: Slide the baking sheet (or transfer the flatbreads via pizza peel) into the preheated oven. Bake for 12 to 15 minutes. Keep a watchful eye on them; they are done when the edges of the flatbread crust have turned a beautiful caramelized golden-brown, the goat cheese is wonderfully soft, and the blueberries are plump, glossy, and beginning to burst their rich juices.
Final Touch and Serve: Carefully remove the sizzling flatbreads from the oven and transfer them immediately to a large wooden serving board. While they are piping hot, elegantly apply a generous drizzle of raw honey or balsamic glaze all over the top. Garnish with the fresh, feathery sprigs of dill and a light crack of black pepper. Slice with a sharp pizza wheel and serve immediately while warm.