In the bowl of your stand mixer, combine the flour and dry yeast, mixing well.
Add the salt and mix again to incorporate.
Slowly drizzle in the cold water and olive oil, then knead the mixture at medium speed for about 8 to 10 minutes.
About 2 minutes before finishing, add the dried rosemary to the dough.
Once kneaded, the dough should be smooth and pull away from the sides of the bowl.
Cover the bowl with a clean, damp cloth and let the dough rest at room temperature until it has doubled in size, which should take about 1 to 1.5 hours.
After the dough has risen, gently press it down with your fist to release the air.
Divide the dough into two equal pieces and let them rest for 15 to 20 minutes, covered with a kitchen towel to relax the gluten.
Roll each piece into an elongated oval shape, about ½ inch thick, and place them on an oiled or parchment-lined baking sheet.
Score each fougasse with a leaf pattern by making two lengthwise cuts down the center and three diagonal cuts on each side.
Gently pull the openings wide apart with your fingers.
Scatter the olives over the dough, pressing some lightly into the surface while keeping others whole or roughly chopped.
Cover the fougasse with a damp cloth and let them rise at room temperature for 30 to 45 minutes.
Meanwhile, preheat your oven to 475°F (240°C) with the fan on.
Mix a drizzle of olive oil with 1 tsp of dried rosemary and brush this mixture over the fougasse just before baking.
Sprinkle a pinch of fleur de sel or flaky sea salt on top.
Bake the fougasse for 12 to 15 minutes, or until they are deep golden brown and sound hollow when tapped on the bottom.
Serve warm.
