Step 1

Using a paring knife, score plums all the way around, starting and ending at stem end and cutting just through the skin (you want to keep plums intact).

Step 2

Bring 2 cups water to a boil in a medium saucepan. Remove from heat, add tea bags, and let steep about 5 minutes; discard tea bags. Add sugar and bring mixture to a boil, stirring to dissolve sugar. Reduce heat, add plums, cardamom, and star anise; scrape in vanilla seeds and add pod. Simmer until plums are just tender, 15–20 minutes. Remove from heat and let plums cool in poaching liquid.

Step 3

Discard vanilla pod, cardamom, and star anise. Halve plums, remove pits, and return to poaching liquid.

Step 4

DO AHEAD: Plums can be poached 2 days ahead. Cover and chill. Bring to room temperature before serving.