In a small saucepot over medium-high heat, bring vinegar, sugar and salt up to a simmer. Heat just until the sugar is dissolved, turn off and set aside.
In a large saucepot, bring water up to a boil with a palmful of salt. Add cauliflower to the pot and cook until tender. Remove and run under cold water then set aside in a large Tupperware.
In the same pot of water, cook the carrots until tender, remove and run under cold water and add to the carrots to the Tupperware along with the onion, olives and hot peppers. Pour the hot vinegar mixture over the vegetables, cover and chill overnight.
Serve alongside Rachael's Porchetta.