In a medium bowl, whisk together the plain flour, gram flour, baking powder and ground turmeric. Add the yogurt and 150ml water and use a wooden spoon to beat together until smooth. Leave in the fridge overnight.
The next day, add the jalebi mixture to the bowl of a stand mixer and beat on medium for 10 minutes. Meanwhile, add the sugar, rosewater extract and 650ml water to a deep, wide saucepan. Bring to the boil, then reduce to a steady simmer for 10-15 minutes until the sugar has completely dissolved and has thickened to a syrup consistency. Remove from the heat and cover to keep the syrup warm.
Heat the ghee in a wide pan with low sides until around 170°C in temperature. Pour the batter into a squeezy bottle, then squeeze spirals of batter into the hot oil. You should be able to fit three in the pan, each one having about 4 coils.
Cook for 1-2 minutes on each side so that they turn golden and are slightly crisp. Scoop them out of the ghee, allowing any excess oil to drip off, then drop them carefully into the sugar syrup for about 30 seconds so they are fully submerged. Lift out and lay on a wire rack. Sprinkle with pistachios and serve still warm.