Add aquafaba and caster sugar into a saucepan.
Simmer on a medium-low heat until the sugar has dissolved and the mixture has reduced to 400 g.
Tip: Weigh the mixture after cooking to ensure it has reduced to less than 400 g. If it is over 400 g, cook for longer.
Transfer the mixture into the Appliance bowl and let cool at room temperature for 1 hour.

Line two baking trays with parchment paper.
Preheat the oven to 85ºC.
Fit the Whisk Tool.
Add cream of tartar into the Appliance bowl.
Mix for 5 minutes on speed Max, until the mixture is light with firm peaks.
Tip: Start on speed Min and gradually increase speed.
Then add food colouring paste of your choice.
Tip: Ensure you use a food colouring paste as water-based food colouring can affect the results.
Tip: Alternatively, divide the meringue into four equal parts to make different colours of kisses.
Mix for 30 seconds on speed Max until combined.
Tip: Start on speed Min and gradually increase speed.

Transfer the mixture to a piping bag fitted with a large open star tip.
Pipe meringue kisses onto the baking trays.
Bake for 2 hours at 85ºC.
Let cool in the oven for at least 1 hour.
Tip: For best results, leave in the oven overnight.

Serve.