Start by first making the chutney. Soak tamarind in water for 2 to 3 hours.
Squeeze pulp with your hands and strain liquid into a saucepan. Discard pulp.
Place saucepan over a medium high flame and add jiggery and salt and let it boil gently. Give the sauce a stir every 5 minutes so it doesn't stick to the bottom of the pan. The sauce will thicken as it boils. It should reach the consistency of pancake syrup. Cool and store on a glass container.
Once the sauce is ready start on the chaat. Wash spinach leaves. Spread leaves on to paper towels and blot completely dry.
Whisk chickpea flour, water and salt till it is lump free. The batter should be watery.
Heat canola oil in a kadhai, wok or heavy bottomed saucepan. It should take a minute on a medium high flame.
Drop a tiny bead of batter into the oil. if it springs back up to the top the oil is ready.
Dip a leaf into the batter, shake off the excess and drop leaf onto the oil. Fry 6 or 7 leaves at a time. The leaves will crisp up in 20-30 seconds. Drain onto paper-lined sheet pan. Finish frying all the leaves in the same fashion.
Have yogurt, red onion, tomato, tamarind chutney and chaat masala ready in separate bowls.
Assemble chaat by placing a handful of spinach in a bowl. Drizzle a tablespoon of tamarind chutney over spinach. Top that with 2 teaspoons of yogurt. Scatter some onion and tomato over spinach. Finish with a liberal sprinkling of chaat masala. And eat ASAP as the spinach gets soggy very fast!