In a small mixing bowl stir together brown sugar and cocoa powder, set aside.

In a medium saucepan, over medium heat, add butter and milk, bring to a slow boil, and let it bubble for 3-5 minutes. Stirring occasionally. Add cocoa and brown sugar mixture, stirring constantly and cook for 2-3 minutes and sauce is smooth.

Immediately remove from heat. Stir in vanilla, marshmallow cream and finely chopped cookies.

Best served over an I Love Ice Cream Cake, ice cream or really just eating straight from the jar.