1. Heat the oven to 180°C on bake (or Vent Bake if you have it).
2. Scatter the whole almonds inside a small ovenproof dish, sprinkle over the salt and water and roast for 10 minutes, or until light-brown. Remove from the oven, chop the almonds coarsely and leave to cool.
3. Line a baking tray with baking paper and spread over the water and sugar. Put in the oven for about 8 minutes, or until the edges of the sugar just begin to dissolve.
4. Reduce oven temperature to 90°C.
5. As soon as the sugar is hot enough, start whisking the egg whites in a free-standing mixer. Once they begin to froth, carefully pour the hot sugar (using the baking paper) into the running mixer and keep on whisking on high speed for 10 minutes, or until the mixture is firm and glossy. Add the vinegar, cornflour and orange blossom water and mix on a medium speed for 20 seconds.
6. Fold in almonds by hand.
7. Secure a sheet of baking paper to your baking tray by placing a little bit of meringue mix at each corner of the tray. Use two tablespoons to scoop out and shape the meringues onto the tray, making 10 similar-sized, swirly balls. Sprinkle a few slivered almonds on top of each meringue.
8. Place the meringues in the oven and bake for 4 hours. Turn oven off and allow to cool completely before removing.