Final answer:
The Muscat grape, especially the Muscat of Alexandria, is used to make the sweet fortified wines of Setúbal in Portugal and Rutherglen in Australia, producing rich and luscious wines with deep flavors.
Step-by-step explanation:
The grape used to make the sweet fortified wines of Setúbal in Portugal and Rutherglen in Australia is the Muscat grape, specifically the Muscat of Alexandria variant and other related types in the Muscat family. In Setúbal, this grape is used to produce Moscatel de Setúbal, a rich, sweet wine with a distinctive musky flavor profile. The Rutherglen region of Australia is renowned for its Muscat-based fortified wines, often referred to simply as Rutherglen Muscat.
These wines are characterized by their luscious sweetness and depth of flavor, often exhibiting notes of dried fruits, spices, and caramel.