What does the cryptic crossword clue "Mixture of it with a rum is sweet (8)" mean?

The definition is "sweet". The wordplay uses an anagram. anagram of IT + A + RUM + IS = TIRAMISU; definition: "sweet" The answer is Tiramisu.

Mixture of it with a rum is sweet (8)

Telegraph Prize Cryptic #3012 | 8 Across | 2019-07-14 flower