In true Indian cooking, everything begins with a three-spice formula - and two of those spices never change. The third spice, the 'headnote spice', depends on the main ingredient (vegetable, pulse, fish or meat). The 'finishing flavours' are added for salt, sweet, sour, bitter, astringency and pungency and also the 'seasoning' - not salt and pepper but salt and sugar. Nisha's 'The Spice Tree' is the beautiful, clever infographic that is the heart of this cookbook, illustrating the traditional flavour formulas.