One surefire way to spark some romance on Valentine's Day is to put together a date night at home that you and your loved one will never forget. That "Coeur de Marron'' is the one.
Chestnuts are healthy and irresistibly tasty: they rank top of the list of nutritious snacks.
This recipe yields 2 heart-shaped stainless steel or silicone mold. Size: length 7.5-inch X 18.75 cm, width 6-inch/15 cm X height 1.9 inch X 4.75 cm. Each cake serves 4 to 5. Make 2 days ahead.
Lemon gel can be subbed for your favorite store-bought lemon or mandarine spread. For the lemon gel, combine sugar and agar agar. Meanwhile, heat up lemon juice along with water and vanilla. Add the sugar-agar mixture, bring to boil and cook for 2 minutes. Cool off and refrigerate until completely set. Then mix using an immersion blender. It should turn into a soft gel. If it ends up too firm, add more lemon juice and mix. The lemon gel can be used as is or with the addition of diced preserved lemon peel. Shape into desired shape using 2.5 ounces/80g max per cake, and freeze.
Grease and flour cake ring or grease and line it with a strip of parchment paper.
Sift flour and baking powder. In the food processor, mix room temperature chestnut cream with the rum. Add soften butter and blend. Scrap out sides of bowl between steps. Add eggs and powders and mix until smooth. Add roasted chestnut and give a few pulses. Fill up prepared mold and bake at 350ºF/180ºC for 30 minutes. To check out doneness, insert a toothpick in the center, if it comes out clean, the cake is done. Cool completely and chill before slicing.
Soak gelatin in cold water to soften, and drain. Heat up chestnuts and pass through a food mill. Transfer smashed chestnuts to a saucepan, add chestnut cream, water, vanilla, rum and simple syrup. Bring to a quick boil, remove from the heat and add the soften gelatin. Transfer chestnut mixture to a narrow container and mix using an immersion blender or pass through a sieve. Shape crémeux into 2 identical hearts (hearts for the inserts can be made out of cake collars) that should be an inch/2.5 cm smaller in diameter than the cake. Freeze chestnut crémeux.
This mousse is based on ganache montée. Soak gelatin in cold water to soften, and drain. Bring to a boil heavy cream and vanilla, and pour in white chocolate. Mix well and add the soften gelatin. Add chestnut cream and the remaining chilled heavy cream, mix well and refrigerate overnight.
Toast walnuts over the stove or in the oven. In a small saucepan, turn honey, water and butter to a dark amber caramel. Toss in walnuts and continue to cook until each nut is well coated with caramel. Transfer caramelized walnuts onto a silicone mat and separate nuts from each other with a spatula. Let cool and store in a seal container.
Line cake ring with cake collars or parchment (stick parchment strip with light coating of cooking spray). De-mold the frozen chestnut crémeux and lemon gel; keep them frozen.
Shave off sponge edges making sure it fits inside the stainless steel mold; it should be about a 0.4-inch/1 centimeter smaller in diameter than the mold. Cut out chestnut sponge into 3 slices (use 2 sponge slices if using stainless steel cake ring, and one for the bottom only if using silicone mold. Note that the sponge uses for the bottom cake shall be thicker.
Whip ganache montée until soft peaks form like so (do not over whip). If using a stainless steel ring, the cake is built from bottom to top, but do the opposite if using a silicone mold.
Place the thicker chestnut sponge in the cake ring and pipe out some chestnut mousse all around and coat the edges with the back of a spoon making sure that no empty spaces are left behind. Add the frozen chestnut crémeux and spread a thin layer of mousse and cover with the second sponge and then the lemon gel insert. Enclose cake with more mousse and even out using an offset spatula. Freeze cake overnight and un-mold. With the mousse leftover, stick 3 caramelized walnuts and freeze.
This hand crafted heart chocolate lace remains optional. I would recommend using chocolate transfer sheet for an easier alternative. Tempered chocolate is required for both. For the lace, you would need additional things such as a few piping cones made out of parchment paper, and a couple of large acetate sheets or Ziploc cut into sheets (do not use plastic wrap). The secret here is to make laces that are well linked to each other from the belt. Chocolate dots are then added in between to strengthen the whole structure. When the chocolate is set, carefully flip over another plastic sheet, and top with a light weight such as another baking mat to keep it flat. Store chocolate decorations under 68ºF/20ºC.
For a change, this cake and chocolate lace are finished with a chocolate enrobage/flocking mixture. A 1:1 ratio of melted cocoa butter and dark chocolate. Sieve through a cheesecloth prior to use. Set enrobage temp to 104ºF/40ºC. Use a clean and warmed up spray gun over frozen cake to create a velvet effect (chocolate lace don't need to be frozen, just chilled). Chocolate velvet spray can be purchased online.
Last touch up: top cake with more caramelized walnut and add one in the center. Then crown the cake with the chocolate lace. Pipe out dots of lemon gel. Enjoy!