I don't have a CLUE what a *Tiramisu* is - but if it's cooked in any way, the actual alcohol burns off, leaving the taste behind.
Personally, I don't think what you did was a slip/relapse.
Now, if you'd known beforehand that it possibly contained alcohol and took the entire thing to the closet to scarf it down - that'd be another thing!
Listen to your sponsor. You HAVE EARNED every second of your 10+ months sobriety!
__________________
"I became insane, with long intervals of horrible sanity.
. . . I drank -
God only knows how often or how much."
Edgar Allan Poe - January 1848
~
Quoth the Raven, "Nevermore."
Edgar Allan Poe - April 1846