Mix the flour and salt in a large bowl. Mix in the water, a little at the time. Rub in the butter until the dough comes together in a ball. Transfer onto a lightly floured work surface; knead for 10 minutes to achieve a smooth and elastic dough.
Divide the dough in 6 pieces; roll out each piece about 2-3mm thick.
Heat a dry, heavy pan or flat griddle over medium-high heat; cook each flatbread for 2 minutes per side.