Surely everyone has their own fake chocolate glaze recipe they stick to. I have my version, too. The glossy acrylic paint or a final coat of varnish just aren't right. So I mix dark brown acrylic paint with some droplets of Still Water (a brand of modelling water, Vallejo product, technically water-based polyurethane dispersion). The Still Water helps the mixture to expand smoothly over the cakes and the glaze has just the amount of shine a glaze should have after drying. Of course you can use this trick for every kind of glaze not only for chocolate.
Here are some miniatures I used this glaze for.
And this is the Still Water.