。
She slowly turned the doorknob.
Literal
[topic-は] slowly door [genitive-の] handle [object-を] turned.
取っ手 ('handle, grip') is the standard word for a doorknob, drawer pull, or any graspable handle — written with 手 ('hand') as the base, which makes the kanji visually intuitive. まわす is the transitive verb 'to turn, rotate' (paired with intransitive 回る 'to spin'). Note まわす is often written in kana, especially in everyday text. The polite ~ました suggests this might be from narrative or formal description.