Add all the milk, heavy cream, sweetened condensed milk, chocolate chips, cocoa powder, vanilla extract, and salt into your slow cooker. Stir well until everything is fully mixed and invitingly smooth.

Cover the crockpot and set it to low. Let it cook for 2 hours, stirring occasionally to prevent any sticking.

Once cooked, gently whisk the hot chocolate to achieve a silky consistency.

Switch the crockpot to the warm setting and pour the hot chocolate into mugs. Add toppings like whipped cream and marshmallows.