Porcellanopagurus is one of the many attempts of Nature to evolve a crab.

—Lancelot Alexander Borradaile
CRUSTACEA. PART II.–PORCELLANOPAGURUS: AN INSTANCE OF CARCINIZATION. 1916

Crabs have been a part of Nature’s plan for over 200 million years. They have persisted through multiple mass extinction events. There are 5 currently known examples of convergent evolution into crab-like body plans (Nature’s aforementioned many attempts). This tendency for crustaceans to form crab traits has been dubbed carcinization.
Carcinization has become a bit of a meme, with crab fanatics dreaming of the day that we all return to crab. Indeed, the creepy crawly (scary scuttl-y?) mythos of crabs has begotten plenty of imaginative horror stories, including movies like Attack of the Crab Monsters (1957); the Clickers series, which features venomous crab-scorpion hybrids; the crab-like descendents of H.G. Wells’ Morlocks in The Time Machine; and the Japanese folk legend that Heikeopsis japonica, the shell of which looks like an angry samurai, are reincarnated naval Heike warriors.

I have long been fascinated by carcinization. Convergence is just so curious, and the idea that all these little oceanic aliens have grown alike apart is both mystifying and satisfying.

So anyways, this past year I saw a photograph of one of the Blaschka glass models of anemones at the Harvard Zoological Museum. I quickly became obsessed with the gelatinous tentacles and the otherworldly combination of purple and orange. Around this same time, I learned of an interesting new oil on the market, made of algae. A spooky sea (haunted hydrology, if you will) themed cake started to materialize in my Projects-To-Make list.
When I researched the Phymactis genus (blister anemones) and found out that funky little false crabs (of the family Porcellanidae) evolved to live in their stinging tentacles and eat their mucus (sorry…), the idea was clinched for this year’s Halloween cake.

The cake base is made of black cocoa spiked with espresso powder, toasted sesame and algae oils, and crumbled roasted seaweed (gim). It’s wonderfully moist and has a salty-umami kick that is super unique. The frosting is a glossy sea salt caramel Italian meringue buttercream with a healthy dose of Maldon to brace the richness.
I sculpted the tentacles and crab out of marzipan as per usual. It’s important to let the crab dry for at least a few days to develop a sugar shell before painting, or the details might get splotchy.

Happy haunting, hunting, and Halloweening all!

Halloween, previously:
Punch Biopsy Cake, or every dermatologist’s dream
Kaonashi/No Face’s Feast Tart with the teeniest tiniest sculptures
Eve’s temptation with bleeding pomegranate
Pumpkin Milk Tea Cake with eenie-meenie piped decorations
Brown butter pumpkin cake with chocolate chili ganache with teeny marzipan pumpkins
Pumpkin and condensed milk cakes, à la tres leches
Edward Gorey-inspired skeleton cat and bat cookies
Ghosts trapped in chocolate ganache on a pumpkin cake
Bats, eyeballs, and pumpkin-moji cookies
Old, old peanut butter cup cake with Reese’s
Of course, this ludicrous bleeding heart cake

Spooky Sea Cake (Black Cocoa, Roasted Seaweed, Algae Oil, and Sea Salt Caramel)
makes a 3 layered 6 inch cake

ingredients:
for the cake:
5 sheets roasted salted seaweed (gim)
330 grams (1 1/2 cups plus 2 tablespoons) sugar
1 1/4 teaspoons kosher salt
1 1/2 teaspoons baking soda
1 1/2 teaspoons baking powder
2 teaspoons cornstarch
180 grams (1 1/2 cups) AP flour
65 grams (1/2 cup plus 1 tablespoon) extra dark/black cocoa powder
2 tablespoons instant coffee or espresso
120 grams (1/2 cup) boiling water
81 grams (1/4 cup plus 5 teaspoons) algae oil
1 teaspoon toasted sesame oil
2 eggs
2 tablespoons vanilla extract
160 grams (2/3 cup) buttermilk

for the caramel:
120 grams (1/2 cup) heavy cream
200 grams (1 cup) granulated sugar
90 grams (6 tablespoons) butter
1 teaspoon sea salt

for the frosting:
3 egg whites
150 grams (3/4 cup) sugar
45 grams (3 tablespoons) water
330 grams (3 sticks, 1 1/2 cups) butter
1 teaspoon sea salt
2 teaspoons vanilla extract

directions:
Make the caramel: heat heavy cream to a simmer, then hold at low temp.
Heat sugar over medium heat, swirling the pan (not stirring!) until it is amber colored.
Pull it off the heat and quickly whisk in the cream, butter, and sea salt.
Allow to cool completely before using.
Preheat oven to 350 degrees F.
Grease and flour 3 6×2 inch pans.
Blitz seaweed in a food processor until it is fine crumbs.
Place sugar in a large bowl, followed by salt, baking soda, baking powder, and cornstarch; whisk together briefly.
Add the flour on top of the mixture, then the cocoa powder, then the instant espresso on top of that.
Slowly stream the boiling water over the cocoa powder; once it’s all added, whisk vigorously while you add in the oil.
Add in both of the eggs and the vanilla extract, then stream in the buttermilk while whisking.
Carefully and fully stir in the seaweed crumbs.
Scrape the bowl to ensure homogeneity, then portion evenly into the three pans.
Bake for 18-22 minutes, until a tester comes out with a few crumbs and the tops are springy.
Allow to cool completely before frosting.
Meanwhile, make the frosting: place egg whites in the bowl of a stand mixer fitted with a whisk attachment.
Place the sugar in a pot with the water and heat over medium heat while whipping the eggs.
Heat the sugar syrup until 240 degrees F; the egg whites should be at soft peaks.
Pour the syrup into the whipping egg whites, being careful not to splash.
Whip until the meringue has reached stiff peaks and cooled to room temperature.
Drop the butter into the meringue 2 tablespoons at time, whipping in between until fully incorporated.
Once all the butter is added, whip for at least 3 minutes, until everything comes together and becomes fluffy.
Add a 1/2 cup of caramel sauce, taste, and add up to another 1/4 cup as desired.
Tint to desired color and decorate with marzipan shapes.