The cake in question has a filling made with heavy cream. Does it need to stay in the refrigerator or will it be okay left out for 24 hours or so?
The sugar will act as a preservative however I just would never leave a cake out for that long.
Anything with a dairy base I refrigerate. Too risky otherwise.
depends on the rest of the recipe. I use 1T of heavy cream in mt buttercream and it is safe at room temp/ If there is more cream than sugar then it will need to be refridgerated
Most cakes have no need to be refridgerated and can stay out, covered in a box or cake case, for up to 5 days with no problems. However if the cream ratio is higher than the sugar ratio then you will need to refridgerate the cake. If you have a fondant covered cake remember that when you remove it from the fridge there will be condensation that will appear on the surface and you will need to give it time to evaporate. Any royal icing decorations may melt with the condensation so you will need to keep that in mind when putting the final decorations on your cake if it needs to go in the fridge.
If the sugar ratio to cream ratio is higher then the sugar acts as a preservative and your cake will be fine covered on the counter.