Top our Ricotta Cheesecake with this compote.
Cut peels from grapefruit and orange. Cut pith from peels, and slice into very thin strips. Slice fruit along membranes to release segments into a bowl. Squeeze juice from membranes into bowl; discard membranes. Pour cup juice through a fine sieve into a small bowl.
Bring a medium saucepan of water to a boil. Cook citrus peels for 1 minute; drain. Bring cup water, the sugar, and vanilla seeds and pod to a boil in a clean medium saucepan over medium-high heat, stirring until sugar dissolves. Reduce heat to low. Add reserved juice and peels and the salt; cook for 2 minutes. Let cool completely.
Discard vanilla pod. Toss syrup with reserved fruit.
Make the compote up to two days ahead.