Parashas Bo · Shemos 12:9 · TT note 8
Torah Temimah on Shemos 12:9, note 8 (on וּבָשֵׁל מְבֻשָּׁל) points to Pesachim 74a.
Sefaria — Exodus 12:9
Sefaria — Torah Temimah on Exodus 12:9
Sefaria — Pesachim 74a
E-Daf — Pesachim 74a
English: And let one bring [a spit] of palm? Because it has fibers, it exudes water and becomes like cooked. And of fig? Because it is porous, it exudes water and becomes like cooked.
Practical application of the ban on cooking: moisture from certain woods turns roasting into cooking.
One may not roast the Pesach on a palm or fig spit, because those woods release water and effectively cook the meat.