Pronouncing it as spelled is acceptable —
— and most common where I grew up in New England.
I looked it up meantime, too, and Oxford agrees that either pronunciation is currently acceptable; "brooch" came into Middle English from French and was based on the French word broche (pronounced BRO-sh), accounting for the long "o" sound in the "broach" version. So the next mystery is where the double "o" came from? LOL!