This simple dish is inspired by a dear old friend, Patti Jackson, who made a dessert like this years ago. I dipped into the parfait and enjoyed the granita and juicy chunks of watermelon against the creaminess of the panna cotta she layered with the fruit. Who would have thought watermelon and something creamy could make such a refreshing and creative combination? Layer this simplified riff in retro sundae dishes or glass—anything transparent. The serving amounts vary based on the size and height of the dishes or glasses you choose.