A verb in the Gnomish Lexicon of the 1910s glossed “scorch” (GL/71), probably based on the early root ᴱ√TORO (QL/94).
Gnomish
brantha-
verb. to scorch
tortha-
verb. to scorch
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
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.