First, make the syrup. Put the sugar and 100ml water in a pan set over a medium heat. When the sugar has dissolved, add the saffron and bring to the boil. Continue to boil for 5-6 mins until thickened and syrupy – the consistency should be like honey. Remove from the heat and add the cardamom and lemon juice – the lemon juice prevents the sugar crystallising. Set aside.
For the batter, put all the ingredients except the baking powder and bicarb, in a large bowl. Slowly add 150ml water and whisk for a few minutes until smooth, then add the baking powder and bicarb and stir well – it should be as thick as pancake batter. Pour into a squeeze bottle with a narrow tip, or spoon into a piping bag and snip off the tip so you have a small opening. Pour the oil into a large heavy-bottomed saucepan until it’s no more than two-thirds full and heat to 170-180C, or until a drop of the batter sizzles when added.
Carefully squeeze or pipe swirls of the batter directly into the hot oil – do this in batches (you should be able to fry four or five at once). Fry for 1-2 mins on each side until golden. Remove the jalebi with a slotted spoon to a plate lined with kitchen paper to drain, then, while still warm, dip in the syrup using tongs or a fork, turning to coat. Sprinkle over the flaked almonds or chopped pistachios. Serve straightaway or leave to cool.