Ingredients :

• All-purpose flour — No need for special flour. Classic supermarket T45 or T55 works perfectly. The important thing is not to overdo it when rolling out — a lightly floured surface, not a snowfield.
• Stone-cold butter — This is the boss of the recipe. The butter must come out of the fridge right when you use it. Cold fragments in the flour create small fat pockets that, when baked, give those crispy layers we’re looking for. Soft butter equals elastic and sad dough.
• Cold water — A few spoonfuls are enough. Add it bit by bit — the goal is a dough that holds together without sticking to your fingers. Better to add more later than to put too much at the start. If you have ice handy, nearly-iced water really makes a difference.
• Filling of your choice — For sweet: thick jam (not too liquid, or it overflows everywhere), chocolate-hazelnut spread. For savory: grated Comté with fresh thyme, or ricotta and spinach. Avoid overly wet fillings that will soak the dough from the inside.