Homemade Truffles

Hi Lindsey
But baffled made Delia's chocolate truffles as I always do love
that you can freeze them.but had 2 funnies this year bought
expensive Couvture to make first lot think I made blunder by putting 2 tbsp of yoghurt in should have been one tasted lovely
but kept very soft mixture so had to put in freezer for a while so
I could roll them so wonder if couvture was also reason covered
Brazils fab.then did usual 70% chocolate and made no errors
with mixture but when they had hardened the butter has come to the top again filling underneath lovely but I am baffled any thoughts would be great
Thanks
Edith