This mix is BIG! And I have tested it in three different tray sizes as follows:
* 1 x single tray base measurement 42cm x 32cm x 1.5cm deep will give a cracker depth of about 1cm;
* 1 x single tray base measurement 38cm x 26cm x 2.5cm deep will give a cracker depth of about 2cm;
* 2 x large slice tins base measurement 30cm x 20cm x 3cm deep will give a cracker depth of about 1cm.
RECIPE UPDATE:
I make this recipe a lot ... and I have come to realise that if I use more egg whites than I originally suggested (i.e more than 70g) then the final baked "snap" it sturdier which I prefer, but if you have made this recipe already and like them just as they are then stick with the original amount of 70g. As I use a lot of egg yolks I always have plenty of egg whites in the freezer ready to use, so this is a great recipe to help use them up.
Over time I have also replaced some of the weight of the seeds with a combination of hemp seeds and buckwheat ... if you decide to do this too, just keep in mind you need a total of 520g seeds (the original recipe uses 220g each pepitas and sunflower seeds, and 80g total of flaxseeds) but you can use any combination of seeds that you like (i.e. the last batch I made used 160g each pepitas and sunflower seeds, 70g each hemp seeds and buckwheat seeds, and 60g flaxseeds).