If you want to stretch it one step further, you can say "Soup/Soupe d'aujourd'hui" instead, since "aujourd'hui", while it's normally French for "today", actually literally translates to "the day or today".
So your sentence would turn into "What's today's soup of the day of today, of the day today?"
At restaurants I always ask:
What's today's soup du jour of the day today?
No waitstaff has ever noticed what I do there.
I see you work for the Department of Redundancy Department.
Yes, our favorite supervillain is Lady Redundant Woman.
If you want to stretch it one step further, you can say "Soup/Soupe d'aujourd'hui" instead, since "aujourd'hui", while it's normally French for "today", actually literally translates to "the day or today".
So your sentence would turn into "What's today's soup of the day of today, of the day today?"
Kek