White pumpkin pieces processed into a completely transparent, glass-like sweet confection using a specific lime-water treatment and sugar syrup — the most famous sweet of Agra, manufactured in thousands of forms and sold near the Taj Mahal.
Ingredients
1 kg white pumpkin (ash gourd — the pale green variety used for petha, not the orange pumpkin)
2 tbsp calcium hydroxide (chuna/lime — food grade; available at paan shops; this is the processing agent)
6 cups water for soaking with lime
For the sugar syrup: 2 cups sugar, 2 cups water
1/4 tsp cardamom powder
a few drops of kewra water
Method
Prepare the ash gourd: Peel the white pumpkin. Remove seeds and fibrous centre. Cut into rectangular pieces about 5 cm x 3 cm x 2 cm.
Poke holes all over: Using a fork or a thin skewer, poke holes all over every piece of pumpkin — top, bottom and sides. About 20 to 30 holes per piece. These holes allow the lime solution and later the sugar syrup to penetrate the entire piece.
Soak in lime water: Dissolve 2 tbsp calcium hydroxide in 6 cups water. Stir until dissolved. Add the pumpkin pieces. Soak for 2 hours. The lime water firms the pumpkin cell structure — this is what allows it to become transparent without turning mushy.
Wash thoroughly: After soaking, rinse the pumpkin pieces in 5 to 6 changes of fresh water until all lime residue is completely removed. Any lime residue will cause bitterness.
Boil until semi-transparent: Boil the lime-soaked, washed pumpkin in fresh water for 10 to 15 minutes until the pieces turn slightly translucent and soft when pierced.
Make thick sugar syrup: Combine 2 cups sugar and 2 cups water. Boil until a sticky, medium-thick syrup forms (about 1-string consistency).
Add pumpkin to syrup: Add the boiled pumpkin pieces to the hot sugar syrup. Cook on medium heat for 20 to 25 minutes, turning the pieces occasionally. The pumpkin will slowly absorb the sugar and turn progressively more transparent as the water in the cells is replaced by sugar.
Cook until fully transparent: Continue cooking until the pumpkin pieces look completely glass-like and transparent — you should be able to almost see through them. This is the characteristic of authentic petha.
Add flavour: Add cardamom powder and kewra water. Stir gently.
Cool and serve: Remove pieces from the syrup. Place on a plate to cool. As they cool the syrup on the surface crystallises into a thin white coating. Serve at room temperature.
Note: Agra Petha is one of the oldest and most well-known regional sweets of Uttar Pradesh — made in Agra for over 500 years and now a GI-tagged product. The Noori Darwaza area of Agra has dozens of petha manufacturers producing hundreds of varieties including plain, angoori (grape-flavoured), pan, kesar and chocolate petha. The key technique is the lime-water treatment that firms the pumpkin cell walls allowing it to become transparent during sugar cooking.