In a large bowl, add water, yeast, and oil. Mix well.
Add flour and salt. Stir with a spoon until combined. The dough will look rough — don’t worry, that’s perfectly fine.
Cover the bowl with cling film and let it rest for 30 minutes in the oven. The oven should be OFF but the light ON — this creates the perfect warm environment for your dough to rise.
After 30 minutes, it’s time to make the dough “dance”: scoop the dough with your hands, lift so it stretches, and fold into the centre — repeat 5 times, once for each side.
Then scoop, lift, and drop — again, repeat 5 times.
You’ll notice the dough is smoother and has some tension on the surface.
Rest again in the oven (OFF, light ON) for 30 minutes.
Remove from the oven and repeat: scoop, lift, fold — 5 times; scoop, lift, drop — 5 times.
Transfer the dough to a 35 x 24 cm (13.8 x 9.4 in) baking tray. Spread it gently with your hands (a little oil helps). Cover and rest for the final 30 minutes (oven OFF, light ON).
Drizzle olive oil, massage the top, then add rosemary and flaky salt. Poke the surface to create classic focaccia dimples. Optional: flick a little water on top to help regulate moisture while baking.
Bake in a preheated static oven at 230°C (450°F) for 15–18 minutes, until golden and puffed.