Mix everything into a very soft, very wet dough, cover and let rest in a warm place for a few hours or overnight. Make sure there’s plenty of room for the dough to rise.
Once the dough has risen to 2-3 times the original volume, knead back into a more compact dough, removing as much air as possible.
In a cast-iron skillet, pour in 1 tbsp extra-virgin olive oil and coat the bottom and sides of the pan.
Transfer dough into the skillet, cover and let rise again.
After 30 minutes, press the dough lightly to flatten and spread it in the skillet.
Baking
Pre-heat oven to the highest setting on your oven (for me this is 220 degrees Celsius).
(optional) Roast the pistachios, and chop roughly into big chunks.
Remove the rosemary stem, and roughly chop the leaves.
Mix olive oil, water, and coarse salt with a fork, until the oil and water form a yellow-green coloured emulsion.
Evenly spread olives, pistachios, and rosemary on the surface of the dough. Lightly press the toppings into the dough.
Drizzle the oil-water emulsion on top.
Bake for 25 minutes (might need adjustments depending on your oven setting), until the bottom is crispy.