How to make ice cream base using evaporated milk easier to work with?
From the clarification in your comments, it sounds like the amount of solids that you are introducing to your recipe is effectively absorbing almost all of the liquid ingredients that are typically added.
If you want the mixture to be easier to manipulate for the churn, I think your best options are to either introduce more liquid (and thus dilute the other solid ingredients) or to reduce the quantity of solid ingredients that you are using in the first place.
Note that as far as I can tell, for the purposes of this recipe with regards to ease of churning, I consider the cocoa powder, dark chocolate, and to a lesser extent egg yolk and evaporated milk as &quot;solids&quot;. These are all things that will cause the liquid in your recipe to solidify faster when chilled vs. the usual liquid ingredients.
Hope this is helpful. Good luck!