Mild Italian cheese made from whey left over after making other cheeses (7)
I believe the answer is:
ricotta
'mild italian cheese' is the definition.
'ricotta' can be an answer for 'cheese' (ricotta is a kind of cheese). I am unsure of the 'mild italian' bit.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for ricotta that I've seen before include "cheese, Italian style" , "cheese found" , "dairy produce" , "Read the riot act about the cheese" , "Sheep's milk cheese" .)