In a small bowl mix together the gelatin and 3 tablespoons of cold water and set aside to soften.
In a medium pot combine the milk, 2 1/4 cups heavy cream, sugar and salt. Put over medium heat and heat until just before it reaches a simmer.
Remove from the heat and whisk in the softened gelatin, instant espresso powder, vanilla bean pod and seeds. Cover and let steep for 30 minutes.
Arrange 10 espresso cups or 10 (4-ounce) ramekins on a baking sheet. Stir the cream mixture to reincorporate all the flavors.
Remove vanilla bean pod from the cream and evenly divide the mixture between the espresso cups. Cover the cups with plastic wrap and refrigerate for at least 5 hours or overnight.
In a large cold bowl, combine the remaining 3/4 cup of heavy cream and the powdered sugar. Whip with a hand mixer until soft peaks form.
Remove the panna cotta from the refrigerator and top each cup with a heaping tablespoon of the whipped cream.
