Sieve maida and salt together in a mixing bowl. Rub in 25 gms of butter and mix in water and lemon juice. Make a dough of elastic quality on a marble, granite or stone surface. Cover it and keep in the fridge. 

Beat the butter till soft and shape it into a thick block of about 1/3". Cover it and keep it in fridge to set.

Roll out the dough, place the butter slab in the middle and fold the dough over it. Keep it upside down and roll it again into a rectangular shape. Fold it into layers. Wrap it in a polythene cover and keep it in the fridge for 2 hours. 

Repeat the rolling and folding process four times resting the dough two hours in the fridge in between every time. 

Cut into squares of 5"x5" trimming the sides so that the layers show up. 

Keep one tablespoon of prepared vegetables and fold it diagonally thus giving the patties triangular shape. Dampen the sides, press them slightly and seal them. 

Brush the top of the patties with milk (optional). Bake them in a hot oven at 200C for about 50-60 minutes or to a golden brown color.