In a medium saucepan over medium heat, whisk together the whole milk, cocoa powder, and sugar. Stir continuously until smooth. Cool and refrigerate for 1-2 hours.

In a large mixing bowl, whip together the heavy whipping cream and vanilla extract until stiff peaks form, around 4-5 minutes.

Once chilled, pour the chocolate mixture into the whipped cream and gently fold together until well blended.

Fold in half of the chopped nuts and mini marshmallows into the ice cream mixture.

Transfer the mixture to a freezer-safe container. Sprinkle remaining nuts and marshmallows on top. Seal and freeze for at least 3 hours.

Let the ice cream sit for a few minutes before scooping. Serve in bowls or cones and enjoy!