Make the chocolate cream:

Place chocolate chips in a metal bowl. Heat 3/4 cup cream in a small saucepan until it bubbles around the edges.

Pour cream over chips, let stand 5 minutes; stir until smooth.

Refrigerate until chilled, about 10 minutes. Using an electric mixer or a whisk, whip the chocolate until smooth and fluffy.

Make the peanut butter cream:

In a medium bowl, whip remaining 3/4 cup cream to stiff peaks. Whisk in sugar. In a medium bowl, fold whipped cream into peanut butter.

Assemble:

Layer graham cracker crust, first with chocolate cream, then with peanut butter cream.

Refrigerate or freeze until firm; sprinkle the peanut butter cream with cocoa or grated chocolate.