i wish i could say i had a fun story for this banana cupcakes with mocha frosting recipe. something that started with, “when i was little…” or, perhaps, “when my husband and i were in (::insert faraway location here::)…”. buuut, these cupcakes came from exactly what you would expect: bananas sitting on the kitchen counter for too long and turning black. once they get past a certain point, their fate is determined and it’s just a question of waiting for them to get a little bit darker and sweeter so that they will be “optimized” for banana bread (aka, more rotten).
i decided to make banana muffins instead of bread (because let’s be honest: muffins cook way faster than loaves of bread) and one night, as i was enjoying a muffin for dessert, i popped some coffee frozen yogurt in the bowl with the muffin because… that’s what we had in the freezer at the time. BAM! it was like a flavor light bulb went off in my head. (is a “flavor light bulb” a thing?? is now.)
banana cupcakes + coffee frosting. that was my next recipe project. knowing that the line between muffin and cupcake is often blurry but that a hefty slathering of butter and sugar was in store for the tops of the cupcakes, i opted for less sugar in the cupcake portion so that our teeth wouldn’t ache when we took the first bite. i did want to have a lighter texture though, rather than a dense, heavy banana bread crammed into a little muffin tin well. i looked at a bunch of recipes and, because i <3 excel and baking is all about ratios, i plugged a couple of leading contender recipes into a little grid so that i could compare the relative amounts of sugar, bananas, and pain-in-the-bum-to-go-out-and-buy ingredients (looking at you, buttermilk and especially crème fraiche).
happily, the recipe that i settled on to try first doesn’t have any annoying ingredients, unless you count 3 tablespoons of leftover coffee as annoying. i don’t drink coffee and, thus, don’t have leftover coffee at my disposal but since we need instant espresso for our frosting, i figured a few tablespoons of coffee wouldn’t be too much of a hardship to procure. the recipe i selected also called for just 2 bananas, which i thought promising in my quest to avoid heavy, dense cupcakes.
for my first trial, i trimmed the sugar just a little bit, based on the ratios i had seen in some of the other recipes and left out the spices (cinnamon and ginger) that didn’t jive with my coffee theme. it turned out pretty well and was almost there. ironically, one of the changes i made for round two was to add one more banana, as i thought the banana flavor could use a bit of a boost. i also swapped half of the white sugar for light brown, as some of the other recipes had called for brown sugar and i like the molasses flavor it contributes.
this whole time that i was tinkering with the banana cupcake portion, i was basically using the same general buttercream recipe, just trying to get the right amount of coffee flavor. i figured out how much instant espresso to use and decided to call it done, but there was a nagging sense in the back of my mind that the frosting was too sweet. i kept ignoring that voice though, because, hey, it’s frosting, it’s supposed to be sweet.
finally “done”, i frosted the cupcakes with the coffee buttercream, took pictures, and then enjoyed eating several of the frosted cupcakes. all the while though… that voice… too sweet.
fast forward a week or two and my next flavor light bulb goes off! i used to love chocolate buttercream for my birthday cakes but over the past few years, i’ve switched to using a chocolate sour cream frosting from my friend meredith because… it’s not too sweet! i pulled that recipe out and set to tinkering to create a less chocolate-y, more coffee-y version of the frosting and, voila! not too sweet, super delicious frosting. yay, finally! so now i can finally stop thinking about banana cupcakes with mocha frosting. by which i mean, eat the rest of the tester i assembled last night and get to work on the next recipe trial…
- 3 ½ oz. (99 g. / 7 tablespoons) unsalted butter, room temperature
- 3 ½ oz. (99 g. / ½ cup) white sugar
- 3 ¾ oz. (107 g. / ½ cup) light brown sugar
- 2 large eggs
- 8 ½ oz. (240 g. / 2 cups) all purpose flour
- 1 teaspoon baking powder
- 1 teaspoon baking soda
- 3 large bananas, peeled and very ripe
- 3 tablespoons cold coffee
- 4 oz. (1/2 cup / 1 stick) butter
- 2 tablespoons instant espresso granules
- 7/8 oz. (25.5 g. / 1/3 cup) unsweetened natural cocoa powder (not dutch processed)
- 3 oz. (88 g. / ¾ cup) powdered sugar (more or less, to taste)
- 3 5/8 oz. (104 g. / scant ½ cup) sour cream (more or less, to taste)
- preheat the oven to 350° F. this recipe makes 16 – 18 muffins so if you have a 12 cup tin and a 6 cup tin, that’s perfect. if not, you can reuse the 12 cup tin for the second round. if your muffin pans do not release muffins easily, grease and flour them. this recipe isn’t particularly sticky, though, so my nonstick tin worked fine without any preparation.
- in a medium bowl, combine the flour, baking powder, and baking soda. mix well and set aside.
- in another medium bowl, mash the 3 peeled bananas and the coffee together until no large lumps remain (i leave small lumps). set aside.
- in the bowl of your stand mixer or a large bowl, beat the butter and sugars until the mixture is light and fluffy. (i used the paddle attachment for my kitchenaid and a speed setting of 4 – 5.) stop the mixer and scrape down the sides of the bowl with a rubber spatula, as needed.
- add the eggs one at a time and beat well after each addition.
- remove the mixer bowl from the mixer and add the dry ingredients, using a wooden spoon to stir them together. mix just until mostly combined then pour in the banana/coffee mixture and stir just until combined. the batter will be lumpy because of the banana so avoid overmixing so that your cupcakes don’t turn out tough.
- fill each muffin tin well about 2/3 of the way full. the batter will rise and spread over the edges if you fill the wells any higher, which tastes fine, of course, but makes for some funny looking cupcakes. this recipe makes around 16 – 18 cupcakes, so if you have empty muffin wells left AND you had greased/floured them, fill them about 2/3 full with water before you put the pan in the oven to prevent nasty cleanup. if the empty wells are clean, no need to fill them with water (mind = blown but america’s test kitchen says so).
- bake the cupcakes for about 16 minutes, checking on them a minute or two before that and leaving them for a few minutes longer if your toothpick doesn’t come out mostly clean. if your oven heats unevenly, rotate the trays halfway through baking.
- once they are done, remove the pans from the oven and let the cupcakes cool in the pan for about 3 minutes, then use a thin, flexible rubber spatula to gently coax them out and onto a wire rack to cool completely.
- in a medium size, microwave safe bowl, melt the butter. i like to melt it about halfway then whisk it from there to avoid having butter explode all over the inside of the microwave.
- add the espresso granules to the butter and whisk to combine as best as you can. this is going to get sort of clumpy and sticky, that’s ok, don’t try to wrestle with it now; it will sort itself out as you go.
- add the cocoa powder and whisk that in. the sticky clumps from the previous step should start to go away at this point.
- add the powdered sugar and the sour cream and whisk until smooth. taste and see if you want more sugar or more sour cream. if you are a math whiz, you will notice that my conversions above for these two ingredients are imprecise. i was measuring in grams and wanted to give you a starting point in the other measurement units but mostly just use the amount that tastes good to you.
- if the frosting is too soft to frost the cupcakes, cover it and let it cool in the refrigerator for about 30 minutes.
- be sure the cupcakes are completely and totally cool, then frost with as much frosting as you like. store leftover frosting/frosted cupcakes in an airtight container in the refrigerator and remove the frosted cupcakes an hour before you want to eat them to allow them to come to room temperature. another option would be to only frost the cupcakes as you plan to eat them so that you only need to refrigerate the frosting and then let that warm up for about 15 minutes so that it’s spreadable.
no nearly rotten bananas languishing on your counter? i haven’t tried this trick yet but i’m totally intrigued and plan to employ it next time the craving for banana cupcakes hits. apparently you can bake bright yellow bananas into ready-for-baking bananas. if you try it, let us know how it goes in the comments.
if you don’t have leftover coffee for the cupcakes, follow the instructions on your instant espresso to produce 1.5 oz. (3 tablespoons) of espresso.
in case you skimmed over it above, the frosting i photographed and the frosting i ended up liking best and detailing here are… not the same. so yours will look darker (and taste better) than what the photos show.
cupcakes adapted from swedish cakes and cookies, frosting adapted from my friend meredith’s sour cream chocolate frosting