Introduction: Luminous Watermelon Salad

About: Enthusiastic cook, blogger and (sometimes) crafter.

 I’ve whipped up a refreshing, chilled summer salad that is visually striking in daylight and (more impressively)  in ultraviolet light. And though the plating makes it look complicated, the elements are incredibly simple. Cucumber and watermelon, when they are cut carefully, look like precious little crystalline gems. The tonic granita is unusual for a salad, but adding a frozen element makes this dish unusual and perfect for enduring the summer heat (I also took some inspiration from ooold, old Roman salad recipes that were served in a bed of snow carried down from mountain tops). Mint-infused oil provides a refreshing contrast to the acidic/bitter granita. And the finishing touch? Salt. I don’t sprinkle salt onto my slices of watermelon (though my grandmother always did) but a sprinkling of salt brings out the subtle flavors of the watermelon and cucumber and nudges this salad firmly into the realm of savory foods. You do need to take plenty of time and effort cutting the fruit, though. Pretty, meticulously cut fruit is what makes this dish elegant. If you happen to have a black light, it is pretty fun to switch off the lights and see this dish glow. But rest assured that it is just as tasty under normal lighting conditions.

For a simple recipe, this one took a long time for me to come up with. I wanted to develop a recipe that could be shown off in ultraviolet light. My plan was to find a few foods that are luminous in ultraviolet light, pick a few that had flavors I liked, whip up a dish then: voilà! I’d have a luminous, delicious dish. But luminous foods proved more fickle than I had planned for, I ended up trying lots of things that just didn’t look interesting under an ultraviolet light. Tonic-candied lemons were de-li-cious, but barely glowed at all. And contrary to what I had read in other sources, pureed greens do not glow red, unless they are pureed with oil, not water (so my layered herbal gin fizz was murky and unimpressive). In the end, I decided to stick with the two most impressive glowing foods (in my own subjective judgement): infused oils and tonic water. The final dish is a rather simple one, where these two luminous elements can show off their unique visual qualities, while each adding a complimenting flavor and texture to the central elements of the dish.

This recipe and lots of other foodie nonsense are also available at my blog,

flaky sea salt

1 lime
1 c. Tonic water*

Mint Oil:
a handful of mint leaves
½ c. grapeseed oil

*Tonic water contains quinine, which causes an allergic reaction in a small percentage of people. Drinking tonic is no more inherently risky than eating other foods with allergens like nuts, meat, fish, eggs, wheat-- you get the picture. Because it is an unusual ingredient, and many people have not heard of quinine allergy, a footnote seemed justified.

Step 1: Prepare Salad Elements

Make Granita

Juice lime and add juice to tonic water. There are endless techniques to make a granita, each technique yielding a slightly different texture. I favor the method of freezing granita in a shallow dish, stirring every half hour or so for the first hour and a half of freezing (though the sugar content of this granita is so low that this step is not quite as necessary). Once the granita is frozen solid, use a fork to scrape off flakes of snowy granita. You can also freeze the granita in an ice cube tray and throw the cubes into the food processor right before serving.

Make Mint Oil

Bring a saucepan or kettle of water to a boil. Pour boiling water over mint leaves and leave them to wilt for one minute exactly. Pull the leaves from the hot water and immediately plunge into a large bowl of ice water. Squeeze excess water from the leaves and throw them into a blender. Blend wilted leaves together with grapeseed oil on high speed for one minute or until leaves are completely pulverized. Strain oil through a tea strainer or several layers of cheesecloth.

Cut Salad

Halve and peel cucumbers, scoop out the seeds with a teaspoon. Cut watermelon and cucumber into very neat, small cubes. Reserve the odd pieces for another use. (Agua fresca, perhaps?)

Step 2: Prepare Fruit & Plate


It is ideal to use chilled plates for this dish. Drizzle mint oil on the plate in a very simple decorative pattern (the oil will move and slide more than an emulsified sauce, so complex patterns do not work well). Place a dessert ring* on the plate and spoon in the cucumber and melon mix. Gently press down on the top of the salad to help it hold its shape, but not so hard as to crush the fruit. Carefully lift the mold away. Sprinkle the plate and top of the fruit with sea salt. Scrape or process granita, and place a generous spoonful on top of the cucumber melon mix. Try to work quickly with the granita, you have a very limited time before it melts, and it is definitely the most impressive element to show off under a black light.  Serve immediately.

Want to prepare ahead?

Cut watermelon and cucumber will keep refrigerated for several days. Mint oil will keep at room temperature for about a week, or refrigerated for several weeks. Granita will keep indefinitely, though you might need to recrush or scrape it before serving.