Over low heat, bring milk, sugar, espresso powder, and salt to a simmer while whisking to prevent milk from scalding.

Once the sugar and espresso powder is dissolved, remove from heat and add chocolate, whisking quickly until chocolate is melted.

Add liquor to chocolate mixture and cool.

Once cooled, gently fold into Greek yogurt.

Pour into four serving glasses and chill for at least 2-3 hours or overnight.