Heat the water, invert sugar and larger portion of caster sugar. Add the pectin and smaller portion of sugar (which you have mixed together in advance).
Once it is at 245°F (118°C), add the acid solution.
Mix together the blueberries, raisins, muesli, puffed rice and ÉCLAT D’OR, then add the hot syrup.
Use a rolling pin to press 650g of the mixture into a 34 x 34cm, 10mm-high frame. Sprinkle with chocolate chips.
Warm the water and incorporate the citric acid.
Mix and leave to dissolve.