Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
ras-
verb. to scorch, toast
brantha-
verb. to scorch
A verb in the Gnomish Lexicon of the 1910s appearing as G. brantha- “scorch”, related to (and possibly derived from) G. brant “cooked, done; overdone” (GL/24).
Neo-Sindarin: I recommend restoring this confluence of Gnomish cooking-related words in Neo-Sindarin based on a Neo-Root ᴺ√BRATH “cook”, and would adapt this word as ᴺS. branna- “to scorch” to better fit Sindarin phonology.
tortha-
verb. to scorch
A verb in the Gnomish Lexicon of the 1910s glossed “scorch” (GL/71), probably based on the early root ᴱ√TORO (QL/94).
A verb in the Gnomish Lexicon of the 1910s glossed “scorch, toast”, related to G. rasc “toast(ed bread)” (GL/65).