Peel and quarter the pears lengthwise, reserving the stems if possible.
Combine the Vin Santo, olive oil, sugar, and ginger in a large bowl. Toss the quartered pears in the mixture.
Transfer the coated pears to a half-sheet pan. Spread them out into an even layer. Roast them in the oven for 30-40 minutes until the pears are tender and lightly brown around the edges.
Prepare the Vin Santo Zabaglione while the pears cool slightly.
Divide the pears between 8 glasses. Spoon the Vin Santo Zabaglione over the pears. Garnish with toasted slivered almonds, anise, and a cookie, if desired.
Vin Santo Zabaglione
Bring a several cups of water to boil in a saucepan set over high heat. Reduce the heat until the water simmers gently.
Whisk together the egg yolks, sugar, and salt in a medium size stainless steel bowl that fits on top of the saucepan.
Whisk in the Vin Santo.
Position the bowl over the gently simmering water. Whisk the egg yolk mixture constantly until the mixture increases in volume and turns a light pale yellow, for from 6-10 minutes.