Add Port, sugar, peppercorns, cloves, and vanilla bean to a 2-quart pot set over medium-high heat and simmer for 10 minutes.
Peel, halve, and core pears, leaving stems intact if possible. Add pear halves to port. Cut out a piece of parchment paper the diameter of the pot and set on top of pears. Add a small heatproof saucer or bowl on top of paper to weight it down and help keep pears submerged.
Reduce heat to low and simmer pears for 8 to 10 minutes until a knife can penetrate pears with little resistance. Remove pot from heat and allow pears to cool in poaching liquid. (You may keep pears in their liquid at room temperature until ready to serve or they can be refrigerated in their liquid for up to one week.)
Remove pears from poaching liquid and set aside. Strain liquid into a clean 2-quart pot. (You should have about 3 cups of poaching liquid.) Scrape vanilla seeds into pot and discard pod along with pepper corns and cloves. Bring liquid to a boil over high heat, reduce to medium, and cook until bubbles are bursting over the entire surface and liquid is reduced by about two-thirds, about 20 minutes. (The liquid should be thick enough to nap the back of a spoon.) Remove from heat and transfer to a small container.
Whisk cream until stiff peaks form.
Serve pears with a drizzle of Port syrup and garnish with crumbled blue cheese, a dollop of whipped cream, pistachios, and mint.