Help with this cake icing/filling

[FrenchLimeBlossom]

Ok, so I made a 4 layer choc cake for DS1 birthday. Second attempt as 1st time the filling was too runny and just leaked out of the layers, so I made the remnants into trifle instead!

Problem is this: the filling still won't set!

It is made with 500g milk choc and 500ml hot double cream, mixed till smooth and chilled overnight for at least 24 hrs. It sets pretty thick in the fridge but as soon as I put one layer of sponge on top of the first and a layer of the filling it starts to seep out at the sides and gets worse the more layers go on.

On the picture it looks thick and solid like butter cream icing - where am I going wrong? I am following the recipe (BBC good food best ever chocolate layer cake - web now says the licence has expired) to the letter but it's not working.....

Anyone got any helpful tips? Could I reduce the amount of cream? Substitute some butter icing for some cream?

Stupid question - is your cake absolutely stone cold before you try to layer it?

Have you tried whipping it after it cools? I used to have this problem, was advised on a wedding cake forum to do this because it crystallises the chocolate and helps firm it up.

Alternatively, try adding some butter, although the ganache won't be shiny if you do that.

Whip it once it comes out of fridge.

Freeze your cake layers, and whip the ganache. I wonder if it's because it's milk rather than dark chocolate - a ganache with those proportions of cream and dark chocolate would set to a truffly texture.

Ooh thanks for the speedy responses ladies! Good tips.

The cake was stone cold today, also left for 24 hours before icing this time round, so not heat from cake layers melting the filling. Good idea re whipping though but I might need to use the mixer as my arms are surprisingly weak!

Also good idea re freezing the cake layers, I had not thought of that.

If neither if those work I might try to vary the proportion of milk chocolate and mix in some dark as well - I think the recipe calls for milk to offset the dark which is used in the sponge mix and retain the sweetness. Perhaps if I used a mix of 1/2 and 1/2 dark and milk it might help to set but keep the sweetness there?

Also try decreasing the amount of cream so it's not a 1:1 ratio chocolate and cream. That will make it firmer

Sounds like a bit if a duff recipe. I would usually do a 1:1 ratio of cream to dark chocolate. For milk chocolate you need less cream. Try 1:2 or even 1:3.

I usually make milk chocolate ganache with 600ml of cream and 1kg of chocolate, so I would reduce the amount of cream (or increase the amount of chocolate) too.

I would whip it.

I use a Larousse gastronomique recipe that has chocolate/butter in the proportions of 150g dark chocolate to 65g butter.

It can be cooled and poured over a cake, when it sets like a peelable layer, or whipped until the colour of a dark milk chocolate when it can be piped on, or trowelled on with a palette knife. It's not crisp, but it is slightly crystalline.