In a large bowl, combine the flour, yeast, salt, and finely chopped rosemary. The fine chopping of the rosemary releases its aromatic oils, distributing flavor throughout the dough more evenly. Add the lukewarm water and olive oil, mixing until a shaggy dough forms. Use a wooden spoon or your hands to bring everything together, then cover the bowl with a damp towel or plastic wrap. Let it rise at room temperature for 40-60 minutes until it has roughly doubled in size and looks puffy and airy.

While the dough is rising, preheat your oven to 425°F. This gives you plenty of time for the oven to reach full temperature and stabilize. Generously oil a baking sheet or focaccia pan (approximately 9x13 inches or similar size) with olive oil, making sure to coat the entire surface including the edges.

Once the dough has risen, transfer it to your oiled pan. Using oiled fingers (this prevents sticking), gently press and stretch the dough to fill the pan evenly, working from the center outward. Don't be afraid to let it rest a minute if it springs back—dough has memory! Once it's stretched to fill the pan, use your oiled fingertips to poke dimples all across the surface, creating those signature focaccia indentations. These dimples not only look beautiful but also help trap oil and seasonings.

Arrange the halved cherry tomatoes cut-side up across the dough, pressing them gently into the dimples so they nestle in and won't slide around during baking. Sprinkle the remaining fresh rosemary evenly over the surface, then finish with flaky sea salt. I like to use Maldon salt here because the larger crystals add a pleasant textural crunch that you lose with fine table salt. The tomatoes will release their juices as they bake, creating little pockets of flavor throughout the focaccia.

Place the pan in your preheated 425°F oven and bake for 35-40 minutes until the top is golden brown and the focaccia has risen noticeably. You'll know it's done when the edges are deeply browned and smell wonderfully aromatic, and the bottom sounds hollow when you tap it gently. The tomatoes should be slightly caramelized at the edges.

Remove the focaccia from the oven and immediately drizzle it with your best extra virgin olive oil (I prefer Filippi Berio for its fruity, peppery notes that complement the tomato and rosemary). Transfer to a wire rack to cool for at least 5-10 minutes before slicing. This brief cooling allows the structure to set while the oil soaks in, and it keeps the inside tender while the crust stays crisp. Slice into portions and serve warm or at room temperature.