I don’t know how I went as long as I have without ever eating a Black Thunder cookie bar. These popular Japanese candy bars consist of a black cacao cookie with crunchy rice and a chocolate coating. They are texturally addictive, and I can only assume that the name “Black Thunder” refers to both the richness of the black cocoa used in the cookie, as well as crackly sound of the rice and chocolate as you bite into it sounding like thunder. I really loved how these tasted, and I wound up eating a bunch of these before running out of them. So immediately after I realized that I had no more Black Thunder candy bars to eat, the gears in my pastry-oriented mind started turning, thinking about how I could try my hand at recreating them, or at least making something inspired by them. And that really was how this recipe started coming together. At first, I wanted to make exactly a Black Thunder bar, but that would not be as fun as trying to reinterpret them. I have not really made a chocolate bar in a long, long time, so I figured, why not make a chocolate bar in that fashion, but loosely inspired by the Black Thunder cookie bar? I initially set out to pair these with caramel of some kind – the idea of salted caramel with the ingredients of Black Thunder sounded perfect – chocolate, puffed rice, caramel all together would be incredible. And that was how we got from Black Thunder all the way to these salted caramel “Black Thunder” bars(I feel quotes are necessary here since mine are not true Black Thunder, even though the flavor comes close)!

For the components, we have a black cacao shortbread, chocolate-coated puffed rice, a salted caramel mousse, and a chocolate magic shell that enrobes the entire thing. Black cacao is an alkalized cocoa powder, which has a richer, fruitier chocolate flavor, similar to an Oreo. With the butteriness of a shortbread cookie, that plus the chocolate-coated puff rice alone already makes the classic Black Thunder treat. However, the salted caramel mousse adds a lightness and another nice hit of saltiness and sweetness that plays off of the chocolate gorgeously. Originally, I was going to make a dulcey ganache, but I ran out of dulcey, and while I could have caramelized white chocolate and used that, I figured that aerating a caramel and forming a mousse of that would be a lighter alternative. And it worked quite well! With the coating of these bars, I went with a magic shell, or a quick-setting chocolate coating, made with dark chocolate and freeze-dried cocoa butter, just to guarantee that the coating will be tempered and have that gorgeous sheen, thin layer, and highly appealing snap to it. Overall, I would still give this recipe a 7/10 in terms of difficulty, because there is a lot of waiting and temperature control involved in making it, but the end result is all the more worth it. I would happily make these bars anytime I get a Black Thunder craving.

Makes 12 bars:
For the black cacao shortbread:
3/4 cups + 3 tbsp all-purpose flour
1 tbsp black cacao powder
1/4 cup granulated sugar
1 stick unsalted butter
1 egg yolk
a pinch of salt
1 tsp vanilla extract

In a bowl, mix together the flour, cacao powder, sugar, and butter until a crumbly dough forms. Mix into that the egg yolk, salt, and vanilla to form your dough. Refrigerate the dough for 10 minutes first. Then roll out the dough to 1/8 inch-thickness. Bake the dough at 375 degrees F for 15 minutes. Then while the dough is warm, cut the dough into rectangles, measuring them to fit the size of silicone bar molds. Reserve any leftover shortbread for garnishing the tops of the bars.

For the chocolate-coated puffed rice:
1/4 cup dark chocolate
a pinch of salt
1/2 cup puffed rice

Over a double boiler, melt half of the dark chocolate completely with salt. Take the bowl off heat and stir in the rest of the chocolate first until that is fully melted in. Then fold into that the puffed rice. Spread the puffed rice onto a lined sheet tray and freeze for 10 minutes. Break into smaller, pinkie nail-sized pieces and keep cold for optimal assembly.

For the salted caramel mousse:
2oz granulated sugar
1/2 tsp maldon salt
1oz whole milk, lukewarm
1 tsp gelatin powder + 2 tbsp cold water
1 tsp vanilla extract
5oz heavy cream, whipped to stiff peaks

In a pot, heat up the sugar and maldon salt until the sugar takes on an amber color and registers to roughly 275 degrees F. Add to the sugar your lukewarm milk and gently stir the sugar and milk together until the caramelized sugar fully dissolves into the milk, forming a caramel. Then stir into that the gelatin powder, mixing until that is melted in as well. Allow the caramel to cool to room temperature before mixing in the vanilla extract first, then folding into that the cream to form your mousse. Transfer the mousse into a piping bag.

For initial assembly:
To start, sprinkle into the bottom of silicone bar molds three to four pieces of the chocolate-coated puffed rice. Pipe the caramel mousse into each mold, filling the molds halfway full. Then sprinkle in one to two more pieces of the chocolate-coated puffed rice. Then pipe into each mold the remainder of your mousse. Press on top of that the chocolate shortbread rectangles. Transfer the bar molds into a freezer and freeze for at least 2 hours before attempting to unmold, keeping the bars frozen solid.

For the chocolate shell:
1 1/2 cups dark chocolate
a pinch of salt
5g freeze-dried cocoa butter

Over a double boiler, melt down 1 cup of the dark chocolate with salt completely. Take the chocolate off heat and stir in the remaining chocolate first, then the cocoa butter. Keep the mixture at roughly 90 degrees F for optimal glazing.

For garnish:
Caramel morsels
Reserved shortbread bits
Reserved chocolate-coated puffed rice

Place your still-frozen salted caramel-chocolate shortbread bars onto an icing rack and pour the chocolate shell over each bar. Tap the bars immediately after glazing to allow any excess to fall off the sides of the bars, then garnish the tops with caramel morsels, shortbread bits, and chocolate-coated puffed rice pieces to finish. Allow the glaze to set before transferring the chocolate bars back to either the freezer or refrigerator. With any excess coating, you can re-heat it as necessary to re-use for any remaining bars.