Black Sesame Mug Cake (Paleo, Gluten Free)

Start-to-finish, this Asian-inspired black sesame mug cake can be made and cooked in your microwave in less than five minutes! Plus, it makes a spooky single serve sponge cake for Halloween! A closeup of a black sesame mug cake in a black mug on a two black plates. The black cake is covered with candy eyeballs. The red banner on the bottom says it is paleo, gluten free, and dairy-free.

Yes, I’ve definitely jumped on the mug cake craze. After coming up with pumpkin, matcha, vanilla, and chocolate mug cake recipes, I decided to tackle a black sesame cake for Halloween—both for the ominous color and the fantastic taste. The resulting black crumb reminds me of the springy chiffon cakes my mom loves to bake—but this single serve cake can be whipped up in a fraction of the time!

Someone revealing the interior of a black sesame mug cake.

What is Japanese black sesame paste?

The key ingredient in this black sesame mug cake is Japanese black sesame paste, also known as kuro neri goma. It’s typically made by roasting unhulled black sesame seeds and then grinding them multiple times through a ceramic grinder to form a smooth and silky black sauce. Flavor-wise, Japanese black sesame paste is deeply nutty and earthy, with only a subtle bitterness.

Where do you buy Japanese black sesame paste?

You can buy black sesame paste online or at your local Japanese market. It normally comes packed in small glass jars or in upright plastic bags with pouring spouts—you can find them stocked near the sesame seeds at the store. Read the label to make sure the only ingredient listed is black sesame seeds.

Before you use black sesame paste, you’ll need to stir it well because the oil can separate, just like other natural seed and nut butters. After opening the jar, keep it in the fridge for up to a month.

Someone stirring a jar of Japanese black sesame paste and an overhead shot of someone spooning it out. It looks glossy black and runny.

What if you can’t find black sesame paste?

If you can’t find Japanese black sesame paste, you can substitute black tahini but the flavor won’t be quite the same. Black tahini has a less pronounced nutty flavor because the seeds aren’t roasted (or only mildly roasted); as a result, it may taste more bitter. On the upside, black tahini is quite a bit cheaper! Also, you can make your own black sesame paste at home but it may not turn out as smooth unless you have a powerful blender or food processor.

Can you make this mug cake in the oven?

Yes, but the resulting cake will taste eggier and the crumb won’t be as springy. (Plus, it’ll take a lot longer!) With that in mind, here are the instructions: Pour the batter into an oven-safe 6-ounce ramekin and bake it in a 350°F oven or toaster oven for 18-20 minutes or a 325°F air fryer for 13-15 minutes. The tiny single serve cake is done when a toothpick inserted in the middle comes out clean. (If you’re worried about cooking food in the microwave, here’s an article from Harvard Medical School that addresses microwave cooking and nutrition.)

Ingredient Substitutions?

Even though I’ve baked lots of paleo treats lately, I’m not a paleo baking expert by any means and haven’t tried this mug cake with every grain free flour on the market or without eggs. If you can’t have nuts, you can substitute cassava flour in a 1:1 manner and it will turn out pretty good—the crumb will not be as soft and bouncy, but you’ll still be pleased with the result. Readers have told me that Bob’s Red Mill Egg Replacer works well in my mug cake recipes, but the cake will not rise as high. If you end up trying an ingredient substitution, please let me know how it turns out in the comments!

Let’s Make a Black Sesame Mug Cake!

Serves 1

Ingredients:

2½ tablespoons (17.5g) blanched almond flour or cassava flour
⅛ teaspoon baking soda
⅛ teaspoon Diamond Crystal kosher salt
1 tablespoon (15 mL) Japanese black sesame paste
1½ tablespoon (22.5 mL) maple syrup or 1 tablespoon (15 mL) honey
2 teaspoons (10 mL) avocado oil or melted coconut oil
¼ teaspoon vanilla extract
1 large egg
1 tablespoon candy eyeballs (optional and they’re definitely not paleo!)

Method:

In a liquid measuring cup, add the almond flour, baking soda, and salt. Whisk until uniform.

A hand is adding salt and baking soda to a liquid measuring cup filled with almond flour.

Add the black sesame paste, maple syrup, avocado oil, vanilla extract, and egg. Whisk the batter until smooth.

Adding the wet ingredients for black sesame mug cake to the liquid measuring cup and whisking it well.

If you want the mug cake to look pretty, pour the batter into a microwave-safe mug (6- to 8-ounce size is optimal). However, you can totally microwave the cake in the glass liquid measuring cup if you want to cut down on dishes to wash.

Pouring the black sesame mug cake batter into a black tea cup.

Place the mug in the center of your microwave (it will rise more evenly in that spot), and cook on high power for 1-2 minutes.

A brunette woman with glasses placing a black tea cup into a microwave.

The black sesame mug cake is finished cooking when it puffs up and a toothpick inserted into the center comes out clean. Don’t worry if your cake looks lopsided or collapses—it will still taste great!

Looking in a microwave at a black tea cup filled with black sesame cake that's puffed up and ready to eat.

I have a 900 watt microwave and my mug cakes are done in 90 seconds. Adjust the cooking time depending on the strength of your microwave—decrease the time if you have a higher wattage microwave and increase it if you have a less powerful microwave.

Two hand holding a black tea cup filled with a puffed up gluten free and paleo black sesame mug cake.

Let the cake cool for a few minutes and top with candied eyeballs, if desired.

An overhead shot of a black sesame mug cake being topped with lots of candy eyeballs.

It’s a perfectly splendid way to teat yourself and your loved ones to a quick, sweet and spooky dessert!

A black mug on a two black plates is filled with a black sesame cake topped with candy eyeballs.

Craving more spooky Halloween treats?

I got you covered! Here are some of my faves:

Yummy Mummies (a.k.a. Halloweenies)
Bloody Eyeballs (Blueberries Stuffed in Longans in Berry Sauce)
Matcha Mug Cake (and decorate it like Frankenstein’s monster!)

Looking for more recipe ideas? Head on over to my Recipe Index. You’ll also find exclusive recipes on my iPhone and iPad app, and in my cookbooks, Nom Nom Paleo: Food for Humans (Andrews McMeel Publishing 2013) and Ready or Not! (Andrews McMeel Publishing 2017)!

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