Thinly slice to florets of cauliflower and immerse them into ice water. Then blend half of the remaining cauliflower and put the mixture into a pot.
Cook for ten minutes and then blend with a drop of olive oil until the mixture becomes even and smooth. Adjust the salt and set aside.
In another small pot, pour the Campari with the sugar and reduce almost entirely. To finish, add a drop of the vinegar and bit of oil and stir as you would a vinaigrette. Clean and marinate the shrimp in a bit of lemon juice, oil, salt and pepper.
Place a bit of cauliflower purée and Campari vinaigrette on a dish, and layer the marinated shrimp atop, along with the small florets of the drained and dried cauliflower.
Finish with the caviar, which should be placed atop and around the shrimp.