Pistachio cream — or pistachio paste — is made by grinding roasted pistachios until they release their natural oils, forming a smooth, intensely flavoured green paste. At FIX, this is blended with a small quantity of tahini and powdered sugar to create the kunafa cream filling. Real pistachio paste is naturally vivid green, deeply nutty, slightly herbaceous, and expensive relative to alternatives. It is the component most commonly substituted by imitators — who use pistachio-flavoured compound, artificial colouring, or cheaper nut pastes — and the substitution is always detectable. The cream should be smooth, not grainy, and intensely pistachio in flavour, not sweet with a pistachio "accent."

Kataifi is a form of shredded phyllo — extremely fine strands of wheat-based dough, traditionally dried and sold in noodle-like bundles. In classical Middle Eastern and Greek pastry, it forms the base and crown of kunafa (Lebanon, Palestine, Jordan), and is twisted into nest shapes for honey-soaked nut pastries across the Mediterranean. In the FIX bar, raw kataifi is toasted in clarified butter until it reaches a specific golden crispness — then cooled completely before being folded through the pistachio cream. This toasting converts the kataifi's texture through the Maillard reaction, creating a dry, airy crunch that persists through the bar's shelf life when stored correctly. The kataifi is not a flavour — it is a texture — and it is the element that makes the FIX eating experience unique in the chocolate world.

FIX uses premium Belgian couverture chocolate — not compound chocolate or mass-market baking chocolate — for the outer shell of every bar. Couverture must contain a minimum cocoa butter content (typically 31–38%) and be properly tempered to form Type V beta crystals, the crystal structure that gives the chocolate its characteristic gloss, snap, and melt. The choice of Belgian couverture is deliberate: the quality of the shell directly affects the quality of the eating experience, and cheaper alternatives produce a dull, waxy result that undermines the pistachio filling. FIX offers the kunafa filling in milk, dark, and white chocolate shells — each producing a meaningfully different overall flavour profile.