In a large bowl, toss pears with lemon juice. Set aside.
In a medium saucepan, combine water, wine, and honey. Add vanilla seeds and pod and cinnamon stick. Stir over medium heat until honey dissolves. Add pears. Cover mixture with round piece of parchment paper. Reduce heat to medium-low. Simmer until pears are just tender when pierced, turning when halfway through cooking, about 15 minutes.
Using slotted spoon, transfer pears to large bowl. Boil poaching liquid until reduced to slightly syrupy consistency, about 2 minutes. Cool syrup. Pour syrup over pears. Cover and refrigerate up to 24 hours.
Whisk sour cream, sugar, and brandy, if using, in large bowl until smooth. Whisk in 1 to 1 1/2 tablespoons chilled poaching syrup.
Thinly slice each pear half lengthwise, leaving slices attached at stem end. Using metal spatula, transfer pears to plates. Gently press on pears to fan slightly. Spoon some syrup over pears. Spoon sour cream alongside each pear half and serve.