For the Espresso Panna Cotta: Heat 3/4 cup cream, sugar and ground espresso over medium-low heat, stirring to dissolve. Bring just to a boil; remove from
heat. Steep 5 minutes. Meanwhile, pour remaining 3/4 cup cream into the top
of a double boiler (not over heat). Sprinkle gelatin over, let stand to soften, 5 minutes. Add warm espresso mixture; place over simmering water; whisk until gelatin is dissolved, 3 to 5 minutes. Strain mixture through cheesecloth-lined strainer. Pour 1/4 cup espresso panna cotta into each of six tall 8-ounce glasses. Cover with plastic; refrigerate until set, about hour. For Espresso Gelatin: Place 1/2 cup chilled brewed espresso in a bowl.
Sprinkle gelatin over, let stand to soften, about 5 minutes. Bring sugar and
remaining 3/4 cup espresso just to a boil; add to espresso-gelatin mixture; whisk to dissolve. Cool to room temperature. Add 2 tablespoons espresso gelatin to eachglass. Cover; refrigerate to set, 40 minutes. Refrigerate remaining espresso gelatin in a small baking dish, covered, to set. For Vanilla Panna Cotta: Combine 3/4 cup cream and sugar in a saucepan; scrape vanilla seeds into cream, add pod, and bring just to a boil. Remove from heat.
Steep for 5 minutes. Meanwhile, in top of a double boiler (not over heat), sprinkle gelatin over remaining 3/4 cup cream; let stand to soften, 5 minutes.
Pour hot cream over gelatin mixture and set over simmering water; whisk until
gelatin dissolves, about 5 minutes. Pour through cheesecloth-lined strainer;
cool to room temperature. Pour 1/4 cup vanilla panna cotta into each glass. Cover, refrigerat 1 1/2 hours to set. To serve, spoon remaining espresso gelatin into glasses on top of vanilla layer.