Fill a large bowl with ice water and set it aside.

Bring a large pot of water to a boil. Cut a small "X" at the bottom of each peach. Carefully drop the peaches into the boiling water and blanch for about 30 seconds.

Remove the peaches with a slotted spoon and immediately plunge them into the ice water. Once cooled, peel off the skins.

In a medium saucepan, combine 1 cup of water, granulated sugar, and the split vanilla bean (or vanilla extract). Bring to a simmer over medium heat, stirring until the sugar is dissolved.

Add the peeled peaches to the syrup and poach gently for about 5-7 minutes, or until tender but not mushy. Remove the peaches with a slotted spoon and set them aside to cool. Reserve the poaching liquid.

In a blender or food processor, combine the raspberries, powdered sugar, and lemon juice. Blend until smooth.

Strain the puree through a fine-mesh sieve to remove the seeds. Taste and adjust the sweetness if necessary, adding more powdered sugar if desired.

Slice the cooled peaches in half and remove the pits. Place two peach halves in each serving bowl or glass. Add a generous scoop of vanilla ice cream next to the peaches. Drizzle the raspberry sauce over the peaches and ice cream. Garnish with fresh mint leaves if desired.