。
She made me a cup of tea.
Literal
She [topic-は] me [to-に] tea [object-を] one-cup made [for me-てくれた].
Two grammar pieces work together here. (1) The classic お茶を入れる ('make tea,' literally 'put tea in') idiom — 入れる, not 作る, because the action is adding tea leaves to hot water. (2) The counter 一杯 (いっぱい) for cups of liquid, placed after the noun-particle pair as a floating quantifier. (3) The ~てくれる auxiliary turning 'made tea' into 'made me tea.' Together, a compact, gratitude-flavored 'made me a cup of tea.'