Sieve together flour, salt, baking soda.
Cut butter in flour with knife.
Rub in with fork or with fingers till mixture is crumbly.
Add enough water to make a stiff dough.
Wrap in plastic, keep in refrigerator till required.
Drain pineapple, crush coarsely, save liquid.
Measure out half cup liquid, if required add water.
Add cornflour, sugar, stir to dissolve.
Cook while stirring continuously, till transparent.
Add pineapple, cinnamon, cook further till thick.
Chill to set well, before using.
Roll pastry with help of dry flour to dust, to 1/8″ thickness.
Cut into 4″ squares.
Place a spoonful of filling carefully at one corner, leaving margin to seal.
Wet edge all around with a drop of water.
Fold free corner over filling, to form a triangle.
Press edges together with a fork of by hand.
Make sure no filling oozes out.
Heat fat in frying pan, till hot.
Let in 2-3 triangles, frying till light golden, over medium-low flame.
Flip sides carefully, fry other side.
Drain, place of kitchen paper, to absorb excess fat.
Cut into 2 halves, serve hot as is, or with vanilla icecream alongside.
Variation: Fillings of apple, grapes, peaches, plums, etc. may also be used similarly.