Use a serrated knife to coarsely chop the chocolate; set aside.

In a saucepan over medium heat, warm the milk until it begins to bubble around the edges of the pan. Remove from the heat and stir in a pinch of salt.

Add the chocolate and stir to dissolve. Return the saucepan to low heat and whisk vigorously to froth.

In a large bowl, combine the cream and powdered sugar and whisk to soft peaks. Add the bourbon and whisk to combine.

Remove hot chocolate from the heat, divide between 2 mugs, and top with the bourbon whipped cream.

Using a fine grater, grate a small bit of chocolate from another Mexican chocolate disk over the whipped cream, then serve.