Put oven on 212°F (100°C) or lower if you can to preheat.
Line at least two large trays with baking paper.
If using, prepare you piping bag with a large star shape nozzle
Put the coffee in a small bowl and add boiling water, mix well to dissolve
Drain chickpea liquid into a bowl. Set aside chickpeas for another recipe. You should have approximately ½ cup plus two tablespoons (150mls) of aquafaba liquid.
Add cream of tartar. Beat well with electric hand beaters or in a stand mixer until firm soft peaks form.
Gradually add sugar, a few table spoons at a time, beating well between additions.
*It is important to beat the sugar in well to form soft peaks again in between adding more sugar. Don't be tempted to dump it all in an once or you will deflate your meringues.
Once all the sugar is well mixed in and you have soft peaks again, add about half the coffee mix. Beat well, then add the rest of the coffee mix. You should have firm, glossy mix that forms distinctive 'peaks' when you run the beaters through it. If not, keep beating.
If using, transfer the mix to a piping bag and pipe onto prepared baking trays. You may need to do this in two batches. If you are not using a piping bag spoon the mix onto prepared trays instead.
Pipe onto trays, you can make small stars or larger cookies as you prefer.
Bake for 1 and a half hours. Turn off oven and leave to cool completely with the door closed for maximum crunch (this can be overnight).
Remove from trays and enjoy! Lovely with a cup of coffee or some vegan or regular whipped cream. Delicious!