Preheat the oven to 180C/160 fan/gas 4 and line a large baking sheet with baking parchment, or use a silicone baking sheet. Write or print fortunes on paper measuring 6cm long by 1cm wide.
Put the egg whites, vanilla, almond extract, oil and 2 tsp cold water into a bowl and whisk with an electric hand whisk until frothy, 20-30 secs. Measure the flour, cornflour, sugar and a good pinch of salt into a bowl, then sift into the egg white mixture. Whisk everything together until you have a smooth batter-like consistency. Chill the mixture for 1 hr.
Next, put a tbsp of mixture onto the prepared baking sheet. Oil a metal spoon, then use the back of it to swirl the mixture out into a 8-10cm circle. Repeat with another tablespoon of the mixture, to create 2 cookies. Make sure there is space between each cookie as they will spread in the oven. It is best to only bake 2-3 cookies at a time, as you will need to shape them whilst they are hot. Sprinkle 1 of the cookies with black sesame seeds, then bake for 10-12 mins until the edges of the cookies turn golden.
One at a time remove the cookies with a palette knife once they are out the oven. You want them to still be soft so you can shape them so work quickly. Turn the cookie over so that the sesame seeds are face down and put the fortune in the middle of the circle. Fold the circle in half to secure the fortune and pinch the 2 edges together to seal. Pop the cookie on the rim of a mug or cup and very gently pull the 2 corners down to get the fortune cookie shape. Hold for 10 secs, then transfer the cookies to muffin tins so that they hold their shape whilst cooling completely. Repeat with the remaining cookie mixture.