It's January, which means two things: it's citrus season (yay!) and it's Kookie House's birthday (yay!!!!!). This cake is here to celebrate both, and it is so so so good. I can't handle how delicious this cake is. To which the copious exclamation points above attest.
There are a lot of s'mores cake recipes out there, but this one is unique--the intensely tangy yuzu juice takes the s'mores flavor combo out of sickly sweet territory and into transcendently delicious territory. This cake is unexpectedly addictive.
Yuzu is a grapefruity-lemon-like fruit from Japan and it's just starting to get popular in the States. Word on the street is you might see a lot of Yuzu in the near future since it was recently discovered it grows well in the Pacific Northwest and growers are starting to invest in it.
In the meantime, you can find some very good fresh bottled Yuzu juice from Japan. I found this bottle above at my local Asian mart. You can also buy it online of course, although it can get pricey that way. If you don't live near a cool Asian food mart and you don't feel like shelling out the bucks for an online order, you can easily swap in regular fresh lemon juice in this cake and it will be just as tasty.
This cake is rich and moist and serves to seal in the graham crackers which keeps them miraculously crispy even though they are baked into the cake. The ganache I use here is even easier to make than buttercream, so don't be intimated. Make the ganache first so it can set up a bit.
This is my basic ganache recipe I use for filling or frosting cakes. If you want a lighter, more buttercream-like texture, whip with whisk beaters for ONE minute (don't over-whip or it can separate). Feel free to double or triple this recipe for bigger batches--this makes just enough to fill this cake.
10.5 oz. chopped dark or semisweet chocolate (chips will work, but finely chopped chocolate is better)
5 fl. oz. heavy whipping cream
Place chopped chocolate into a heat-safe bowl. Microwave or heat cream on stovetop until just barely simmering around the edges. Pour slowly and evenly over chocolate. Twist bowl back and forth gently so the cream covers the chocolate completely. Allow to sit for 30 seconds, then begin stirring with spatula or whisk. Mix until completely smooth and no lumps remain. Allow to cool for at least 30 minutes before using. If it sets up solidly before using, microwave for a few seconds until it softens to peanut-butter like consistency.
Now, a lot of "marshmallow" frosting recipes are really just meringue--egg whites, sugar, lots of tiny bubbles. And yeah, you can cover your cake with light and foamy meringue and toast it, and that's nice. But if you want something really marshmallowy, you need to get some gelatin involved.
It seemed most logical here to use actual marshmallows in the recipe than deal with gelatin, since the marshmallows will offer up their gelatin to us AND their marshmallowy flavor. This marshmallow frosting is ridiculously delicious and its simple, I promise. I could eat gobs of it alone. You can just glob it on your cake or pipe it--either way it looks beautiful. And toasted?? Even better. I used my kitchen blowtorch which is one of those kitchen tools you don't use all of the time, but when you need it you really need it.
3 large egg whites, cold
1/2 c. cold water
1 1/2 c. (325 g.) sugar
1 1/2 tsp. (12 g.) corn syrup
1 c. mini marshmallows
1 tsp. fresh lemon juice
1 tsp. vanilla extract
Prepare piping bag if using. Mix all ingredients except marshmallows, vanilla and lemon juice in a large metal or glass bowl. Place over a pot of simmering water (do not let the bowl touch the water). Using electric beaters, beat steadily on medium high speed for about 7 minutes or until mixture holds stiff peaks. Remove from heat and add remaining ingredients, beat until marshmallows are completely melted. Scoop immediately into prepared piping bag or swirl onto cake quickly, as this frosting will set up as it cools.
Now onto the main event. This is my new go-to winter cake.
YUZU S'MORES CAKE
3 c. (350 g.) cake flour (White Lily)
3 tsp. (10 g.) aluminum-free baking powder
3 large eggs
2 large egg whites
2 c. (400 g.) sugar
1/3 c. yuzu juice
1 tsp. fine sea salt or kosher salt
1 c. sour cream
1 Tbsp. vanilla extract or one vanilla bean, scraped
2/3 c. canola or vegetable oil
18 graham crackers (2 packages) broken into large pieces
Preheat oven to 350 degrees F.
Whisk flour and baking powder together thoroughly in a large bowl and set aside. Cover bottoms of greased and floured 8" or 9" pans with broken graham crackers. Beat eggs, egg whites, sugar, salt, vanilla and yuzu juice for one minute (use a timer) on medium high until mixture is thick. Continue to beat while adding in sour cream in spoonfuls, and beat until smooth for 30 seconds.
Add oil to the flour mixture and beat until a dough forms. Add 1/3 of the liquid mixture and beat until smooth and lump-free. Repeat with the remaining 2/3rds, scraping the bottom of the bowl and making sure no lumps remain.
Divide batter among pans and tap on the counter to remove large air bubbles. Bake for 35 minutes or so until centers are fully set and spring back when pressed. Allow to cool for 10 minutes, then invert cakes onto cooling rack. Allow cakes to cool completely before filling with ganache and covering with marshmallow frosting. Toast with blowtorch.