Marshmallow Creme-Hot Fudge Sundaes

• 12 ounces semisweet chocolate, chopped
• 1 teaspoon unsweetened cocoa powder
• 1/2 teaspoon instant espresso or coffee
• 1 cup plus 2 tablespoons heavy cream
• 6 tablespoons marshmallow creme

Vanilla ice cream

1. Combine chocolate, cocoa powder, and espresso in a large metal bowl. Bring cream just to a simmer in a small saucepan over medium heat; pour over chocolate mixture. Let sit for 30 seconds, then whisk until smooth and glossy. Fold marshmallow creme into chocolate. DO AHEAD: Can be made 3 days ahead. Let cool, cover, and chill. Rewarm before serving. Serve warm sauce over ice cream.