Preheat oven to 450 degrees. Line cookie sheet with aluminum foil or parchment paper.
In a large bowl, mix olive oil and fish sauce. Core cauliflower and break into small size flowerettes. Toss the cauliflower with the oil/ fish sauce mix until pieces are coated. Add the peanut sauce mix and stir together until cauliflower is covered. Spread cauliflower on cookie sheet in a single layer. Roast for 20 minutes or until cauliflower is tender-crisp and edges are tipped with brown. Serve as an appetizer with toothpicks or as a vegetable side.