Coconut Sugar Banana Sheet Cake with Caramelized Coconut Sugar Frosting

This week’s recipe for From My Kitchen Friday is a throwback to my last book, Real Sweet. It had been a while since I’d baked up this recipe, and I have to say, it’s just as good as it ever was!

Although its not a slam dunk for every baked good, when you find a perfect recipe to use coconut sugar, it’s as though the heavens open up as you take a bite. Because it’s not derived from sugar cane, the “brown” flavor of coconut sugar doesn’t come from molasses, and so it tastes quite different from other brown sugars like turbinado or muscovado. It’s a decidedly exotic, toasty flavor that pairs wonderfully with other tropical flavors, especially bananas. 

Speaking of bananas, one of the tricks of using coconut sugar successfully in baking is to find a recipe that has plenty of tenderizing, moisture-lending ingredients in it—like  mashed bananas or other fruit purees, oils, and buttermilk or yogurt—as coconut sugar tends dry out baked goods. 

When caramelizing the coconut sugar, keep a close eye on the thermometer, and pull the pan from the heat the moment the temperature hits 248°F—coconut sugar can burn quickly past that point and take on a somewhat astringent taste.  Speaking of the frosting, although the liquid sweetener here obviously adds sweetness, its main function is to keep the caramel flexible and add a beautiful gloss to the whipped frosting. I like to use something very neutral in flavor like brown rice syrup to allow the coconut sugar flavor to really shine, but you could also use light agave, mild honey, or even coconut nectar, if you have it, which will give a much deeper color to the frosting and make it a bit sweeter, as well.

Coconut Sugar Banana Sheet Cake with Caramelized Coconut Sugar Frosting

Makes 1 9-by-13-inch cake 

2 cups (9 ounces/255 grams) unbleached all-purpose flour, spooned and leveled

2 teaspoons baking powder

1/2 teaspoon baking soda

1/2 teaspoon fine sea salt

1 cup plus 2 tablespoons (6 ounces/170 grams) coconut sugar

4 tablespoons (2 ounces/57 grams) unsalted butter, at room temperature

2 large eggs, at room temperature

1 teaspoon pure vanilla extract

1 1/3 cups (10 5/8 ounces/302 grams) mashed bananas (from about 3 very ripe medium ones)

2/3 cup (5 3/8 ounces/151 grams) Greek yogurt

1/4 cup (2 ounces/56 grams) coconut or vegetable oil

Caramelized Coconut Sugar Frosting (see recipe below)

Position a rack to the center of the oven and preheat it to 350°F. Spray a 9-by-13-inch pan with nonstick spray or butter it generously. 

Into a medium bowl, sift together the flour, baking powder, baking soda, and salt.

In a separate medium bowl, whisk together the mashed bananas, Greek yogurt, and oil until smooth.

In the bowl of an electric mixer fitted with the paddle attachment, beat together the butter and sugar on medium-low speed until the mixture looks like dampened sand, about 1 minute. Add the eggs one at a time, giving the first about 30 seconds to incorporate before adding the second.  Increase the speed to medium-high, beating until light in texture and much paler in color, 4 to 5 minutes (don’t skimp on the beating time, here—the significant change in color will be your cue that the sugar has begun to dissolve). Beat in the vanilla extract.

Reduce the mixer speed to low. Stir in the dry ingredients and banana-yogurt mixture in five alternating additions, beginning and ending with the dry ingredients, letting each addition fully absorb into the batter before adding the next. Finish folding the batter gently by hand to ensure it’s well-blended. 

Scrape the batter into the prepared pan and smooth the top. Bake until a toothpick comes out clean, 25 to 30 minutes. Cool the cake completely in the pan on a wire rack. Keeping the cake in the pan for easy transport and storage, slather with Caramelized Coconut Sugar Frosting. 

Caramelized Coconut Sugar Frosting

Makes about 1 1/2 cups 

9 tablespoons (4 1/2 ounces/128 grams) unsalted butter, cut into tablespoons and softened, divided

3 tablespoons (2 1/4 ounces/63 grams) brown rice syrup or light agave nectar* 

1/4 teaspoon fine sea salt

3/4 cup (4 ounces/113 grams) coconut sugar

1/4 cup (2 ounces/58 grams) heavy cream

1 1/2 teaspoons pure vanilla extract

In a medium, heavy-bottomed saucepan set over medium heat, melt together 4 tablespoons of the butter, brown rice syrup, and salt. Add the coconut sugar and stir with a heatproof spatula. Bring the caramel to a gentle boil and clip a candy thermometer to the side of the pan. Cook until the temperature reaches 248°F, about 5 minutes. Remove the pan from the heat and carefully stir in the cream and vanilla. Set the pan aside to cool for 10 to 15 minutes. 

Whisk the remaining 5 tablespoons of butter into the caramel, one tablespoon at a time, letting each knob of butter absorb into the caramel before adding the next. Don’t rush this step—you’re not only setting yourself up for a nice emulsified frosting, you’re also slowly cooling the caramel, both of which will make for a smooth, creamy final product. 

Scrape the now heavily-buttered caramel into a mixing bowl or bowl of a stand mixer. Chill in the refrigerator until the caramel is cool to the touch all the way through, about 20 minutes. Using an electric mixer fitted with the whisk attachment or a handheld mixer on medium speed, whip the caramel into a lush, creamy frosting until light and fluffy, about 2 minutes. (If it still looks like caramel sauce after 1 minute of beating, stick the bowl back into the fridge to chill further before whipping again.) Use immediately, or store in a tightly covered container in the refrigerator, and then bring it back to room temperature before giving it a quick rewhipping.