Place the pears in a nonaluminum saucepan large enough to hold them lying down. Add the wine, sugar, lemon zest, vanilla bean and the water.
Place pan over medium high heat and bring to a boil Reduce heat to medium-low, set a heatproof plate on top of the pears to keep them submerged in the liquid and simmer gently until a thin knife inserted into the widest part of a pear pierces easily to the center, 35–40 minutes. Remove the plate covering the pears. Let the pears cool to room temperature in the liquid.
Meanwhile, make a raspberry purée. In a food processor or blender, purée the berries until smooth. Pass the purée through a fine-mesh sieve held over a bowl, pressing with the back of a wooden spoon to push as much of the purée through the sieve as possible. Discard the contents of the sieve. Set the purée aside.
Using a slotted spoon, lift the pears from the liquid. Set each pear upright in a shallow individual bowl, or place all 8 pears on a deep platter. If necessary, gently trim the bottom to make it flat. Remove the zest and vanilla bean and discard the vanilla bean. Drizzle the raspberry purée onto the plate and garnish with a few fresh raspberries and a vanilla abeam. Serve at room temperature.