。
She stirred her tea with a small gold spoon.
Literal
She [topic-は] small gold [genitive-の] spoon [with-で] black-tea [object-を] stirred.
ちいさな is the kana spelling of 小さな — note that this is the 連体詞 (rentaishi, attributive-only) form of the adjective 小さい, used exclusively before nouns and not as a predicate (you can't say *ちいさなだ; you'd say 小さい). 紅茶 ('red tea / crimson tea') is Western black tea — a culturally important distinction in Japan, where 茶/お茶 by itself usually defaults to green tea. The で marks the gold spoon as the instrument of stirring, the standard で-marking for tools and means.