i only made ganache one other time, in which i let it cool then whipped it.
so this is the first time i am using it warm, to drip over the edge of a buttercream frosted cake.
i need this for tomorrow.
so yesterday i had a small practice cake in my freezer, i let it thaw, frosted it, then tried out the ganache, using a one to one ratio of chocolate to cream. maybe i should have used less cream.

i heated the cream in the microwave to just boiling, then poured it over the dark chocolate chips.
first problem is that when the chips were all melted, there were flecks of darker chocolate, and a few small lumps that wouldnt melt. so it wasnt smoothe, like the first time i made it.

i put the bowl in the refrigerator to cool it down, frequently stirring it, waiting for it to thicken. it took forever to get to the point where it wasnt too runny. i poured it on the cake, it still seemed too runny, so i put it back in the refrig to cool more. it looked ok on the cake, but was thin, and you could see the pink buttercream through it. so i chilled it again, planning to put another thicker layer on the cake. after about an hour it finally looked like the right consistency (but still had the small flakes and lumps), so i poured some on the cake, and it caused the original thin layer to slide off, exposing the pink icing underneath.

i'm making a new cake today, will put the buttercream frosting on it tonight and refrigerate it (because it will have whipped cream and strawberries between the layers). tomorrow, i plan to take it out of the fridge, make the ganache, and pour the ganache over it.

questions:
1) should i bring the cake to room temperature before pouring the ganache, or pour it on a cold cake?
2) how do i prevent the flecks from forming, and the small chunks?
3) will the ganache melt some of the buttercream, or did i only have that problem because i tried to ganache the cake twice?
4) will refrigerating the cake after the ganache is on, hurt the ganache?