Heat oven to 120°C, Gas 1. Line 2 baking sheets with baking paper. Whisk egg whites until stiffly peaking – tip the bowl, the eggs are ready when they don’t move.
Gradually whisk in the sugar 1tbsp at a time until glossy.
Take a plastic piping bag and squeeze in several vertical lines of the gel colour, directly from the tube.
Spoon in the meringue and snip off the end of the piping bag. Pipe small blobs onto baking sheets, Bake for 1 hour until meringues are firm. Leave to cool, then add to a zip lock bag and bash with a rolling pin until you have large and small meringue crumbs.
Spoon a thick layer of quark into a sundae glass and gently fold through 2 tbsp of the Bonne Maman Rhubarb Conserve, then top with crushed meringue pieces and a scattering of pistachios. Repeat with the rest of the glasses.
Make up the meringue and store in sealed jars for up to 2 weeks.
