Biscuit = 饼干 [bǐng gān]
Two ways to dunk a biscuit in tea: four seconds later, one has crumbled to bits, and the note says the other tastes better. Either way, it is a 饼干.
饼干 (bǐnggān) means “biscuit,” “cookie” or “cracker.” 饼 is a flat cake and 干 means dry, so it is a “dry cake.”
A packet of biscuits is 一包饼干 (yì bāo bǐnggān); one biscuit is 一块饼干 (yí kuài bǐnggān).
我喜欢把饼干泡在茶里。 — Wǒ xǐhuan bǎ bǐnggān pào zài chá lǐ. — I like dunking biscuits in tea.
你要吃块饼干吗？ — Nǐ yào chī kuài bǐnggān ma? — Would you like a biscuit?