Hallo Ben - I responded to your query on the 7 April, but the post was wiped in the hack.
Both American and French ice cream were served aboard - Samuel pointed out the 'American ice cream' entry, and in First Class we find, for example, on the 14 April that French ice cream was on the menu (Archbold and McCauley provide some interesting general background on ice cream in 'Last Dinner on the Titanic', including Dolly Madison's famed role in the history of its development in America).
Punch Romaine also appears on the menu - a sorbet-like palate cleanser served between the fifth and seventh courses.