Introduction: How to Make a Glowing Dessert!
This Instructable aims to teach you how to harness the luminescence of common foods - some of which you might already have in your pantry - to create a beautiful dessert that will surprise both geeky and culinary friends alike. This project juxtaposes my love for food, science, and, dare I say, art in one single plate. The idea behind it was to capture a glowing seascape, or the way I imagine the seafloor of a bioluminescent lagoon at night. The top image is the dessert in normal light and the bottom one is the dessert seen under UV light. Almonds – more precisely, the riboflavin in them, - honey, and chlorophyll are foods that absorb ultraviolet light and emit it in visible colors. I had seen quinine, but not these other ingredients being used for their luminescent properties in a dessert, and so I decided to give it a go. What you have here is my attempt at a cohesive dish that would offer different pops of color and interesting tropical tastes at the very same time.
I hope you enjoy it!
Note: to get the bottom picture I bought a small UV lamp from Amazon for less than $8 (http://www.amazon.com/Ultra-Blacklight-Flashlight-Zoom-Light/dp/B00ESJ80NS).
Step 1: Soursop Panna Cotta
473 mL (a pint) of heavy cream
95 g sugar
120 mL soursop pulp, thawed if previously frozen
1 gelatin sheet (22 cm x 6 cm)
Place the heavy cream and sugar in a saucepan over medium heat in order to dissolve the sugar. Once the cream is beginning to steam on the surface (not boil) and sugar crystals no longer remain, turn off the heat.
Submerge your gelatin sheet in a bowl of cold water until pliable (this should take around 45-60 seconds, but will depend on the temperature of your water so do not walk away. I learned this the hard way, when my first gelatin sheet "disappeared" into the water!). Once it’s pliable remove from the water and squeeze the excess water with your hand. Place in saucepan with warmed cream/sugar mixture. Stir until dissolved. Stir in the soursop pulp. Staring the mixture to avoid any pieces of gelatin that might not have dissolved. Pour the mix into your desired serve ware. With shallow bowls like the one I used, I find it easiest to fill them once they're already in the fridge. It will take around two hours for a medium to thin layer to set in the fridge.
Note: soursop has been defined to me by some as an "acquired taste," so feel free to change the fruit pulp used to something else. I used soursop because it would not dye the milk too much, maintaining the white backdrop I was looking for. Also, I've found the brand of soursop affects the texture of the dessert quite a lot, so I recommend La Fe, which so far has produced the best results.
Step 2: Almond Sand
60 g unsalted butter, room temperature
25 g light brown sugar
25 g white sugar
½ teaspoon vanilla extract
1 small egg
40 g almonds
30 g all-purpose flour
Pinch of baking powder
Generous pinch of salt
For subsequent steps: 1 Tablespoon melted unsalted butter, 1 Tablespoon brown sugar
Preheat oven to 350°C. Toast your almonds in a shallow saucepan over medium heat until they are warm to the touch and the oils begin to be released (you can also toast them in a tray placed on an oven preheated to 350°C). Wait for the almonds to cool and place them in a small food processor, process until almonds resemble coarse sand.
Next, place the softened butter and both types of sugar in a stand mixer fitted with the paddle attachment or a hand mixer, mix on medium speed until light and fluffy. Add the vanilla extract and the egg and mix until combined. Turn of the machine and add the crushed almonds, the flour, the baking soda and the salt. Mix on medium-low speed until mixture is combined. Place a sheet of parchment paper or a silicone mat on a baking tray and extend the almond cookie dough into a big oval (the shape doesn’t matter a lot!).
Bake for about 10 min, the edges should be light brown and the entirety of the cookie should be cooked but soft. Take it out of the oven and let cool. Crumble the soft cookie into a bowl and mix with the melted butter and the brown sugar (it should look like coarse sand crumbs).
Place the crumbs in a sheet tray covered with parchment paper/silicone and bake until golden brown, around 5-10 min. Take out and let cool.
Almonds are very high in riboflavin, or Vitamin B2, which is a natural UV light absorbent that emits light back to us in a greenish-yellowish color!
Note: this technique of baking a cookie and then crumbling it and mixing it with more butter and sugar I learned from a Christina Tosi recipe.
Step 3: Honey-Rum Pearls
500 mL of water (or 500 grams, water is easy that way!)
2-3 g sodium alginate (my scale doesn't have decimals, but it should be 0.5% by weight of the water)
75 mL of water
25 mL of rum (I used white Bacardi)
50 mL of honey
5-6 g calcium lactate
1/2 teaspoon of xanthan gum (optional)
Prepare the bath by placing the water in a blender and adding the sodium alginate while the machine is running. The mixture should not have any clumps. It will likely be filled with many small bubbles, so it should be laid to rest for about 2 hours in a bowl, until the bubbled disappear. Meanwhile, place the honey, the calcium lactate and the water in a container. Mix until no clumps remain. After the mix is homogenized, add the alcohol.
The honey-rum mixture needs to be more viscous than the bath to make the pearls easier to make, so you might want to add half a teaspoon of xanthan gum to make it thicker. When it reaches the desired consistency, empty into a container and wait until most of the bubbles disappear. At the top, there will likely be foam, this can be removed with a spoon and discarded, because the liquid should be as bubble-free as possible to make clear pearls. Take a curved teaspoon measure and fill it with honey-rum mix, very carefully and in one swift motion, dump the contents on the bath (this requires some practice, the first ones may look a bit weird but it gets easier with time!). Ideally, the spheres should not touch when in the sodium alginate bath. Leave the spheres in the bath for a minute, remove and place in a bowl of clean water to rinse. Then, store in a bit of leftover rum-honey mixture until ready to use. Honey emits visible light, however I've read the color emitted strongly depends on the quality of your honey: yellow means your honey is high quality, green means it's not!
Step 4: Beet Microwave Cake
80 g sugar
Pinch of salt
75 g fresh beet juice (you might want to buy the juice if you can find it, but I love orange-beet juice so I'm happy to do it the long way!)
40 melted unsalted butter
30 g all-purpose flour
Crack the four eggs into a mixing bowl fitted with the whisk attachment, whisk on medium-high speed until fluffy and doubled in volume. Add the sugar and the salt. Add the beet juice and the melted butter. Finish by adding the flour at a lower speed (so that it stays in the bowl!). Take a .5 L iSi Whip and place a colander on top, strain your cake batter into the whip and close it.
Then, charge the batter with two nitrous oxide chargers.
Make four slits in the bottom of an 8 oz paper cup and fill it 1/3 of the way with the beet batter, cook in a microwave for 40 seconds. Remove the cup and invert until cooled. Use a knife to dislodge the cake from the cup and tear it (freeform is best I think!) into the desired shape.
Note: I like Dixie cups best because you can rip them easily if the cake gets unruly
Step 5: Basil-Mint Oil
Handful of basil
Handful of mint
Mild tasting oil of your preference (I used canola)
First, begin by setting up a blanching station with a pot of boiling water in one side and a bowl of cold water in close proximity.
Submerge the mint and basil leaves for 30 seconds in the boiling water and then remove them and place them in the cold water. Dry them thoroughly with a kitchen or paper towel and place them in a blender.
Blend the blanched leaves with canola or any other mild-tasting oil you have at hand. The amount of oil you use will depend on the height of the blades of your blender, but always start low, because we want this oil to be as concentrated as possible. I used about a quarter cup (or four tablespoons) of oil in total, but your machine might either function well with a little less or require a couple more tablespoons.
Lastly, pass the oil through two sheets of paper towel (or one folded in half) to remove any big pieces that the machine might have left.
The oil might sound like a bizarre addition, but it’s the only way to extract the chlorophyll found in green plant leaves, which is responsible for the red color in the UV-lit dish!
(Instead of just placing the oil on the dish, I brushed it on some Bilimbi, but more on that in the next section!)
Step 6: Plating
To finish the dessert, I highly recommend two types of fresh fruits. Because the theme is underwater (and because I get free starfruit from my tree!) I chose starfruit to decorate. The second fruit I used is Bilimbi, from a tree that grows in my school (it tastes like a mix of starfruit and cucumber). I've never seen them in the supermarkets, but don't worry! The bilimbi is only the canvas in which the basil-oil is painted, so you can use any other fruit you like (apples, pears, mangos, etc). The oil is what gives the red luminescence in the dessert, so its base can be truly anything you want!
To plate, take the panna cotta from the fridge and set a strip of almond crumble sand on top. Place the pieces of beet cake on top, followed by the starfruit slices and the honey-rum pearls. Finish with the cut (and brushed with oil!) slices of fruit and edible flowers (in this case pink/purple Dianthus were used but this is a matter of personal taste!).
Thank you for reading about this project, I hope you like it!