To a large bowl add the flour, sugar, and salt and mix them together. Add the cold cubes of butter to the flour.
Use a pastry cutter to cut the butter Into the flour roughly, but not too small. A few small pieces are fine but the rest can be left in fairly large chunks. If the butter is melting at any point, place the bowl in the refrigerator.
Pour the lemon juice into the ice-cold water. Drizzle it in slowly, a tablespoon at a time, into the dough. Use a spatula or your hands to combine it into a shaggy dough. Add enough water as needed but not too much. Add any extra water slowly, a tablespoon at a time.
It should hold together easily when pressed but not be sticky. If the dough is super crumbly, add a bit more water. You don't want it sticky, though.
Form the dough into a mound and let it chill in the fridge for 10 minutes. If your room temperature is very cold, you can begin rolling right away.
On a floured work surface, roll the dough with a rolling pin into roughly a 5x10inch rectangle. You will see large chunks of butter in the dough. Dust off any excess flour from the top of the dough.
Fold the bottom third of the dough up to the middle, then fold the top third of the dough over top to make a pamphlet shape. That was Fold 1. Turn the dough a quarter turn and roll it back out into a rectangle and repeat the folding. That was fold 2.
Repeat this process 4 more times so you do 6 folds in total. If you are making this on a cold day then there is no need for any fridge rest in between the rolling of the layers unless the butter is melting. In the summertime, the rough puff pastry will likely need a fridge rest in between every second fold to ensure the butter stays chilled. After the last fold, wrap the dough up tightly in plastic wrap and place it in the fridge for a minimum of 2 hours or up to 24.