01 -
In a slow cooker (3-quart size), stir together milk, half-and-half, broken chocolate pieces, sugar, cocoa powder, vanilla, espresso powder (if using), and a bit of salt.
02 -
Use a whisk to mix everything for about 1-2 minutes, making sure no cocoa clumps are left.
03 -
Cook on low for 2-3 hours or set to high for 45-60 minutes, whisking every 45 minutes to keep things smooth.
04 -
When the mixture is hot and the chocolate's melted, switch to the warm or low setting. Spoon into mugs and top with your favorite goodies.