Step 1Stir the gelatin into the cold water and let it sit until the water is absorbed. Stir in the hot water, 1/3 cup sugar and the espresso powder until the gelatin and sugar dissolve.
Step 2Refrigerate until the mixture just begins to thicken but is still pourable, whisking occasionally, about 30 to 60 minutes.
Step 3Whip the cream with the 2 teaspoons of sugar and the vanilla until it's very thick. Whisk half the whipped cream mixture into the espresso mixture. Pour it into a 5-cup souffle dish or bowl. Refrigerate until firm, at least 6 hours or overnight, covered. Refrigerate the remaining whipped cream separately, covered airtight.
Step 4To serve, spread the remaining whipped cream over the Bavarian cream. Garnish with the bittersweet shavings, if using.