Since even the smallest amounts of fat prevent the beaten egg white from becoming firm, wipe out a metal or glass bowl with some lemon juice. Add the egg white to the bowl. Add 2 teaspoons of lemon juice to make the mixture more stable when whipped. Whisk with the whisk of the mixer at medium speed, then continue whisking at the highest speed.
When the mixture begins to stiffen, add the sugar by the spoonful. When all the sugar has been stirred in, continue beating until the sugar has dissolved.
The beaten egg white is ready when the mixture is shiny white and sticks compactly to the whisk.
Halve the mixture as desired and carefully and evenly stir in other ingredients (for the hearts, e.g. beetroot juice) using a dough scraper, not a mixer.
Preheat oven (electric cooker: 100 °C/circulating air: not suitable/gas: see manufacturer). Line two trays with baking paper. Place the piping bag with star-shaped spout in a high mixing bowl and beat the upper edge over the edge of the mixing bowl. This makes it easy to fill in the white meringue.
Spray about 40 small tuffs onto the baking tray, bake for about 45 minutes (heat your oven strongly, check after 40 minutes already!). The tuffs should still be a little soft on the inside and are intended to be eaten soon (or see "This way it stays fresh longer"). Pour the pink mixture into a piping bag with perforated spout, squirt about 40 hearts onto the baking tray, just as the tuffs are baking. Take out, let it cool down.