The Elm architecture seems to use pretty much this exact pattern. The imperative shell parts are all buried within the Elm runtime, and you contribute the functional bits. Redux also to a lesser extent.
Have been using Elm architecture for a while, and also have pushed my code toward an immutable core/mutable shell architecture since watching Vladimir Khorikov's video on the subject at Pluralsight, but had never considered how the two are interrelated. Thank you for the big light bulb lighting up in my head just now.
