01 - In a medium saucepan, combine rolled oats, milk, brewed coffee, cocoa powder, brown sugar, and salt. Stir thoroughly to dissolve cocoa powder.
02 - Bring mixture to a gentle simmer over medium heat, stirring occasionally to prevent sticking.
03 - After 3 to 4 minutes of simmering, add raisins and continue cooking, stirring frequently, until oats are creamy and most liquid is absorbed, approximately 7 to 8 minutes more.
04 - Remove saucepan from heat and stir in vanilla extract.
05 - Divide the oatmeal into two bowls and top with dark chocolate chips, toasted walnuts, and a splash of milk or cream if desired. Serve warm.