a sweet food made from key limes, eggs, and condensed milk (= thick, very sweet milk sold in a can), usually on a pastry base and sometimes with meringue (= light, sweet food made by mixing sugar with egg white) on top

Key lime pie is a popular American dessert.

For dessert, mum baked a key lime pie with meringue on top. 甜点是妈妈烤的一个酸橙派，上面放着蛋白糖酥。