Place marshmallows, 3/4 cup cream, chocolate, cocoa and espresso powders and salt in a medium saucepan over medium heat and cook until melted and smooth, stirring frequently. Transfer to a large mixing bowl and let cool to room temp.

In a stand mixer fitted with the whisk attachment, or in a bowl with a handheld mixer, whisk the remaining cream and vanilla on medium to medium high speed until stiff peaks form.

Gently fold the cream into the cooled chocolate mixture in three additions until combined.

Transfer to six 6-ounce ramekins and serve immediately with additional whipped cream or refrigerate until chilled.