Flame Flan absorb fire and resist physical attacks. Like all flan, they lunge at their opponents and there is a Killsight chance when dodging a lunging Flame Flan, and then hitting them right after.
Because flan resist physical damage, only the strongest physical damaging cadets, Cinque and Jack, are likely to do any decent damage with normal attacks. Magic (outside of fire magic) works well and will likely kill the flan in one hit. Approaching them and enticing them to lunge and then dodging to open the Killsight chance is also a quick way to deal with them.
Flan is an open pastry or sponge cake containing a sweet or savory filling. A typical flan of this sort is round, with shortcrust pastry, usually coated with sweet syrup. It is similar to a custard tart or a South African melktert.