When we serve friends this chocolate potato cake, we often get a puzzled look as they try to wrap their brain around how this dowdy vegetable and the elitist, gourmet chocolate come together in a cake. A kind of culinary tale of the prince and the pauper. Any dubious hesitation when first tasting it is transformed by the delight of a divinely moist crumb, the soothing richness of deep, dark chocolate and the spirited buzz of the Bailey’s Irish Cream filling. Perfect for St. Patrick’s holiday, this cake is a salute to the Irish and their long, historic affair with the humble potato.
The small amount of cooked, riced (or mashed) potato adds a subtle density and a whole lot of moistness to the cake’s crumb. Using top quality chocolate, with 70% cocoa solids, will take this cake from great to sensational. Although the amount of sugar may seem high, it is balanced by the rich, deep bitter flavors in the chocolate, resulting in a cake that is big on flavor without being overly sweet. We add 1/8 teaspoon coffee emulsion, just enough to rock the chocolate’s earthy notes.
Prepping the chocolate and dry ingredients: Melt the chocolate in a heat proof bowl, by setting over simmering water, making sure the water is not touching the bottom of the bowl. Stir until smooth and set aside to cool. The chocolate can also be melted in a microwave oven, just make sure it is not overheated or nuked at too high a setting.
Pulse the flour, almond flour, baking soda, baking flour and salt in the bowl of a food processor 4-5 times, until thoroughly mixed. If you do not have a food processor, sift these ingredients together.
Preheat the oven to 350 °F (170 °C) and place the rack on the lower third of the oven.
Beat the butter and sugar in the bowl of an electric mixer fitted with the paddle attachment, until light and fluffy (3-4 minutes).
Lightly whisk the eggs together with the flavorings. Gradually add the egg mixture to the butter mixture, beating well after each addition. The mixture will be slightly darkened like ours, if using the coffee flavoring.
With the mixer on low speed, add the cooled, melted chocolate, mixing just until incorporated.
Add the completely cooled, riced/ mashed potatoes, gently mixing until combined.
Gently fold in the prepped dry ingredients (in thirds), alternately with the buttermilk, beginning and ending with the dry ingredients. Fold just until there is no trace of the dry ingredients, taking care not to overmix the batter. Lastly, gently fold in the chocolate chips.
Pour the batter into the prepared pan, smoothing the top with a spatula. Bake in a preheated oven for 25-30 minutes, or until a cake tester comes out clean and the center springs back when lightly pressed. Rotate the pan halfway through the baking period for more even baking.
The sides will begin to pull away from the pan when finished baking. Cool in the pan for 5-7 minutes, running a spatula between the pan and edge of the cake before releasing the sides. Remove the cake and cool completely on a cooling rack. Make the cream filling and chocolate glaze while the cake is cooling.
The filling only has 3 ingredients and takes about 5 minutes to make. Bailey’s Irish Cream, with its fusion of Irish cream, quality spirits, aged, smooth Irish whiskey and unique chocolate blend, perfectly accentuates the flavors of the cake, adding a richness that elevates whipped cream to a sanctified cream filling. Adding it to coffee/ espresso, whether hot or cold, transforms it into a spirited dessert beverage that is hard to beat. In a medium size bowl, beat the whipping cream, Bailey’s Irish Cream and vanilla on medium high speed, until they reach the medium peak stage. Do not overbeat. Cover the filling with plastic wrap and refrigerate until ready to use.
As for the cake, the glaze will only be as good as the quality of chocolate used. The glaze is best made with a quality bittersweet chocolate with 64-70% cocoa solids. We like using Lyle’s Golden Syrup, as we think it adds more flavor than light corn syrup, which can be used in its place. The cream should be a double or heavy whipping cream.
After rough chopping the chocolate, place it in a small, heat proof bowl and set aside. Heat the golden syrup and cream in a small sauce pan to just under boiling, gently stirring occasionally. When small bubbles first begin to form on the outer edges, remove from heat and pour over the chocolate.
Whisk gently, until the chocolate has melted into a smooth, glossy mass. So very enticing – the only thing that keeps me from throwing all daintiness to the wind and slurping up the entire bowl is that I still have to glaze the cake. Let cool to room temperature before using, about 15 -20 minutes. If need be, it can be thinned with a little more warm cream.
Before assembling the cake, carefully trim any raised edges around the outside edge of the cake, as shown above. Use a sharp knife to avoid jagged edges and remove any loose crumbs. Use a sharp knife to avoid jagged edges and remove any loose crumbs. With a long, narrow serrated knife, cut or torte the cake into two layers. Start on one side, at the middle of the side of the cake. Slice horizontally through the cake towards the center, while rotating it, until you have two equal layers. We chose to make two 2-layer smaller cakes (4 3/4″/ 12 cm) this time, an option that does not require the cake layer to be cut in half.
Spoon the filling onto the center of the bottom layer of cake. The amount will depend upon your preference. Using an offset spatula, spread the filling from the center, outwards, to within 1/4″ of the outer edge of the cake. If needed, add more filling until there is an even thickness of filling. Place the top layer on to the filling and press down gently until it is firmly set in place.
The chocolate glaze must be thoroughly cooled to room temperature, or it will melt the filling when passing over it as it moves down the side of the cake. However, the longer it cools, the thicker it will become, so after 10-12 minutes of cooling, begin checking it every few minutes, until it is the desired consistency. I find it easiest to pour when transferred to a container with a pouring spout. A pyrex liquid measuring cup is ideal for this. To prevent the glaze from setting before the cake is fully glazed, it is important to have everything ready and set to go (mise en place) and to work quickly. If you don’t want any excess glaze to pool on the cake plate, transfer the cake to a cooling rack with a pan or waxed paper underneath. Pour a pool of glaze on the center of the top layer and then use an offset spatula to spread the glaze towards the outer edge of the cake, allowing it to spill over the edges and down the sides of the cake. I continue doing this until I have the desired thickness on top and ‘drips’ down the sides of the cake.
Although one of its main ingredients has humble beginnings, this cake is the belle of ball with its rich and decadent flavors and polished finish. Enjoy!