Yotam Ottolenghi and Sami Tamimi of London-based restaurant and deli Ottolenghi (ottolenghi.co.uk) say the secret to their famous meringues is a good freestanding electric mixer. Making them by hand is out of the question (your arm muscles would never cope) and using a handheld electric mixer is not practical – the mixture gets too firm for most machines. They recommend heating the sugar to help it cook the egg white as the meringue is being beaten, this gives a stable mixture.
Heat the oven to 200C/fan 180C/gas 6. Spread the sugar over a large oven tray lined with baking parchment. Heat for 8 minutes or until the sugar is hot (over 100C). it should be beginning to dissolve at the edges.
When the sugar is almost ready, start whisking the egg whites on a high speed and let it work for a minute or so, until the whites just begin to froth.
Carefully pour the sugar slowly on to the whisking whites. Once it’s all in, add the rosewater and whisk on a high speed for 10 minutes or until the meringue is cold. It should be very thick and look silky.
Turn the oven to 110C/fan 90C/gas ¼. Stick baking parchment to 1 or 2 baking trays with a bit of meringue. Spread the pistachios over a flat plate.
Use a large spoon to scoop up a dollop of meringue the size of a medium apple then use another spoon to scrape it off onto the plate of pistachios. Roll so it is covered with nuts on one side then gently lift it onto the tray. Repeat, spacing the meringues well apart, they will almost double in size.
Cook for about 2 hours. Check they are done by lifting them from the tray and gently prodding to see if the outside is completely firm. Leave to cool. The meringues will keep in a sealed container for a few days.