This seems like a basic question, and easily google’d, but where’s the fun in that? My question is this: if I were to say “I’m going to be ____ at the stake,” which is the proper word to use? “Burnt” at the stake doesn’t sound right, but neither does “burned.”
Well, it might not be so easy to google as you’d hope, because actually either is acceptable.
“Burned” and “burnt” are two equally good ways to form the past participle of “burn.” The -t ending is just a variant of the -ed ending that reflects how -ed tends to get pronounced after short vowels. Some words, like slept and felt, always form the past participle with -t; some, like beamed or jumped, never do; and some can take either ending equally well, like burned/burnt, dreamed/dreamt, or leaped/leapt.
These -t endings are somewhat more common in British English than American English, although the -ed endings certainly also exist in BrE, just as the -t ones do in AmE. Learnt, spoilt, and spelt (as the past tense of spelled, not the grain), for example, are all more common in BrE.
So whenever a word has two perfectly cromulent past participles, I recommend trusting your ear. After decades of experience with your native tongue, you are eminently qualified to pick between two correct options.
Although personally, I think I’d say “burnt.”