What's the chocolate icing called that you make, pour over a cake and then it sets?!

[Snowstorm]

Have got a complete blank!
TIA.

Do you mean ganache?

It made me think of Ice Magic, but that's just for ice cream, right?

Ganache - that's the one! Thanks very much. Now to Google a recipe for it for DD's birthday cake.

Ganache doesn't really set, it's more of a thick fudgey thing.
I think you might want to look at glace [with an accent] which is shiny and looks great on top of a cake - it's thin too.
Gently melt together 50g grated chocolate, 1 tbsp water, 2 tsp butter and 100g icing sugar.
Let us know how it goes

Oh .... might be glace icing - will Google that too! She just wants a cake with drippy chocolate icing down the sides, like in cartoons etc.

One from Larousse is

65g butter
150g melted plain choc

Melt together, allow to cool a little and pour over cake.

Your can also beat/whip with a balloon whisk to form and it forms a sort of frosting type icing that you can spread with a palette knife. Named as picky-cake icing by dd for obvious reasons. (We came down the following morning to find holes where it had been picked at.)

Oooh thanks! Will definitely try that.

Best chocolate ganache ever (and makes good drips!) is a tin of condensed milk mixed with 250g melted chocolate. Just heat it all together gently in a pan and splodge on.

Got a few birthdays coming up - will try that one too! Now not to lose this thread until I need it ...