On average, 10 million people tuned in to see 19-year-old Flora Shedden leave the show after her showstopper cocoa carousel failed to win over the judges.
The audience peaked at 11.2 million shortly before the end. On average, Bake Off drew 43% of the TV audience.
Tamal Ray, Ian Cumming and Nadiya Jamir Hussain will do battle for the Bake Off crown in the tent next Wednesday.
Last week, ratings for the BBC One baking show took a dip of 1.6 million, after it was scheduled opposite a special live edition of Coronation Street.
This week, its closest rival was ITV's All Star Mr & Mrs - which also ran from 20:00-21:00 BST - drawing an average of 3.1 million viewers.
Flora was eliminated despite impressing both judges with her chocolate souffle in the technical challenge.
Her signature dish, a passion fruit and chocolate tart with macarons, failed to impress on flavour, while her showstopping chocolate centrepiece was deemed "wonky" and "bitter".
"It doesn't taste as good as it looks," said Berry, of the elaborate biscuit and cake carousel.
The university student admitted there "were moments [on the show] when I did feel my age and that I was lacking a certain experience".
"I really never expected to get to the semi-finals, but then I didn't expect to get into the tent in the first place," she said.
Nadiya was made star baker for the third time, matching Ian's earlier successes. The pair will be joined by Tamal as they compete in next week's final episode.
Last  year's final drew a record-breaking audience of 12.3 million, peaking at 13.3 million.
The semi-final of The Great British Bake Off recorded its highest ratings of the series so far.