Make the infused bourbon: Combine the bourbon, figs, pears and vanilla seeds and pod in an airtight container. Let infuse in the refrigerator for at least 2 weeks but no more than 3 weeks. Strain through a fine-mesh sieve.
For each drink, combine 2 ounces of the infused bourbon, the aperitif and vermouth in a mixing glass with ice. Stir for 90 seconds, then strain into a chilled martini glass. Garnish with a slice of orange.