Inspiration for my next dessert recipe usually comes unexpectedly.  This time, I was just poking around at one of my favorite markets and came across a beautiful little bottle of soy sauce.  The decorated label magnetized me with phrases like “small batch”, “non-GMO”, “limestone filtered Kentucky spring water”, “brewed and aged in bourbon barrels”.  But it was the description of the taste that made my dessert goggles sparkle around my eyes like magic: “hints of oak and a mild sweetness reminiscent of fine Kentucky bourbon.”  With my whiskey cupcakes fresh in my mind, I knew this soy sauce was destined to become my next dessert.  Before I knew it, I was headed home excitedly with the little bottle in hand.

My first taste of the soy sauce revealed a high quality, robust flavor that was pleasantly rich, salty, and a bit malty at once.  I couldn’t think of a better match than molassesy dark brown sugar, and my first version of this cake was based solely on this complementary pair.  But I craved more complexity and slightly different ingredient ratios, resulting in this delicious final edition (which happens to be in my oven once again as I type this).  Cooked in a skillet and embellished and enhanced with tangy oranges, the cake’s interplay of brown sugar, butter, and salt spontaneously create succulent butterscotch that’s present in every moist bite.  Here is the recipe.

Brown Sugar Soy Sauce Cake [makes a 10″ skillet cake (see note below); serves 10-12]

• 1 – 2 small/medium oranges, preferably seedless, such as navel
• 1/4 cup plus 1/3 cup unsalted butter*, divided
• 2 teaspoons plus 3 tablespoons high quality soy sauce, divided
• 1/2 cup plus 1.25 cup firmly packed dark brown sugar*, divided
• 2 large/extra-large eggs
• seeds scraped from two medium/large vanilla beans, or 1/2 teaspoon vanilla bean paste
• 1 tablespoon pure vanilla extract
• 1.5 cups flour
• 1.25 teaspoons baking soda
• 1/2 teaspoon baking powder
• 1/4 cup cold water
• 1/2 cup milk

Preheat oven to 350 F.  Rinse, dry, and finely zest the peel of one orange; set zest aside.  Slice orange horizontally in 1/4 to 1/3″ thick rings.  Look over the slices for any wayward seeds, picking them out with a paring knife as needed.  (If orange slices don’t fit in pan as whole circles, feel free to cut edges as needed.  If one orange is not enough to cover the bottom of the pan with slices, you may need to repeat the zesting and slicing process with a second orange, but please only use the amount of zest in the batter from the first one.)

In a 10″ ovenproof skillet, melt 1/4 cup butter with 1/2 cup brown sugar, whisking over low/medium heat.  When butter has melted and sugar starts looking less grainy, let bubble while whisking for another 30 seconds or so.  Remove from heat, whisk in 2 teaspoons soy sauce, and stir until even. Gently lay the orange slices in one layer on the butter mixture, prettiest sides down. Set pan aside.

In a separate container, melt the remaining 1/3 cup butter; set aside.  In a large bowl, beat the remaining 1.25 cup brown sugar with the eggs.  Beat in the melted butter until smooth, gradually adding both vanillas.  Sift the flour, baking soda and powder over the egg mixture.  Begin to mix (batter will seem dry), gradually adding the milk, water and 3 tablespoons soy sauce as you go. Scrape bowl often with spatula as you mix well. Fold in orange zest until evenly dispersed. Gently pour batter onto the orange slices in skillet.

Place pan in center of oven and bake for about 35 minutes*, until center no longer jiggles when shaken and a wooden skewer or toothpick inserted in the middle comes out batter-free (a few moist crumbs are fine).  Carefully remove cake from oven (handle will be hot). Let cool in pan for 30 minutes to an hour, until pan is still quite warm but cool enough to handle.  Loosen sides of cake with a butter knife and gently invert cake onto a large plate. Serve warm, cutting into pieces with a sharp knife straight through the orange slices.

For premium texture, this cake is best eaten soon after baking; but if you must wait longer than noted above, leave it in the skillet until ready to serve (up to overnight).  After it’s completely cooled, cover loosely with foil.  When ready to serve, remove foil, place skillet over low-medium heat for about a minute to help loosen the oranges, then loosen sides with a butter knife and invert. For gooey deliciousness, heat slices up.

With its crisp caramelized bottom and its gooey, buttery top, this citrusy cake is as beautiful as it is delicious.  The splash of robust soy sauce imbues the cake with a perfect amount of salt, balancing beautifully with the brown sugar and creating a layer of tender, butterscotchy topping that caramelizes and permeates the orange slices.  Hints of the soy sauce’s dark, brewed flavor are present in every bite, but without being overpowering or obvious about their origin. What’s more: the cake is a cinch to make, with a one-bowl batter and a simple flip-and-serve method (the decorations are built-in).

Maybe next time…  The soy sauce I used had a deep, robust flavor.  If you use a low-sodium or more diluted-tasting soy sauce, you might add another teaspoon to the buttery topping and/or replace a teaspoon or two of the water with more soy sauce in the batter.  The orange slices could be replaced with thin slices of another fruit, such as pears, peaches or apples (but please keep the orange zest in the batter — it’s wondrous!).  As with many desserts, this one is heavenly alongside a scoop of vanilla ice cream — what isn’t?

*Some notes on ingredients and equipment:

• Be sure to use unsalted butter in this recipe.  The soy sauce provides plenty of salt.
• I  realize the volume of sugar here seems like a lot, but this amount offers a delectable balance to the subtle salt and malt flavor of the soy sauce.  In the different versions of this recipe I tested, this amount proved best.
• Every pan is a little different: darker pans can bake hotter and faster; shallow pans may not fit all the batter; measurements are often subjective (my pan is 2″ deep; it’s marked as 10″ pan, but it’s only 9.75″ across the top at the widest part).  I recommend beginning to check the cake for done-ness at 25-30 minutes, and placing a layer of foil on the oven rack below it in case of spillover (but stop filling it if the batter gets too close to the rim as you pour it in).  Be sure to use an ovenproof pan; seasoned cast iron is my favorite, but almost any all-metal kind should work.