In a large bowl, mix all your liquids.

Add the baking powder and some flour; keep mixing until the dough starts to thicken.

Turn the dough out onto a well floured surface.

Gradually add the rest of the flour and knead for about 20min. till you have a soft & smooth dough (in a stand mixer or a kneading machine, it takes 5-8 min).

Cut the dough into 4 equal pieces, cover with a clean towel and let them rest for 20 min.

Flour your working bench; take one piece of dough, flatten it a bit with your hand and start rolling out.

With a thin rolling pin, roll out the dough till you get a pastry sheet 40cm/16 inches in diameter.

Brush the entire surface with melted margarine.

Fold the two sides to the center. Brush with margarine.

Fold in half and brush again. You now have a rectangle about 40x12cm/16x5 inches.

Mark the center, and fold the two sides towards the middle. Brush again.

Fold in half and you're done. You now have a large pastry sheet with 16 layers that you can roll out any time you wish to make a pie.

Wrap the sheet with food membrane and place it the fridge.

Repeat the same process for the other three pieces of dough.

If you're going to use them the same day, put them in the fridge for 2-3 hours, until firm. Otherwise, store them in the fridge maximum for a week or in the freezer, up to 3 months.