Almond-Rum Cake with Royal Icing (gâteau nantais)

I had fun developing this recipe. It’s my version of a well-known cake from the city of Nantes, a large port (hence the rum) in Brittany. I made several attempts before I achieved the texture I was seeking. I love working without a recipe to follow, and finding the solution on my own. It’s like chemistry: use a little more or less sugar; modify the quantities of butter, flour, and eggs, and the cake turns out differently each time. This cake has a good amount of both ground almonds and brown rum, meaning it keeps well. I couldn’t tell you exactly how long it keeps, because it’s usually devoured pretty soon–though it does improve from one day to another. It can be topped with royal icing, which is then cooked until it is firm enough to form a protective shell, ensuring that it doesn’t dry out. This also allows the flavors inside to develop more fully.

Recipe for the Almond-Rum Cake

Makes one 6-inch / 15 cm diameter cake. For one 8-inch / 20 cm cake, double the quantities given below.

• 6 tablespoons / 95 g butter
• Generous 2/3 cup / 130 g) sugar
• 1/3 cup / 45 g flour
• Generous ½ cup / 150 g finely ground blanched almonds
• 1 tablespoons plus 2 teaspoons (25 ml) brown rum (if you prefer, use the same amount of orange flower water, or 1 tablespoon pure vanilla extract)
• 1/3 cup / 90 g eggs (the equivalent of two SMALL eggs)

• 2 tablespoons (30 ml) rum for moistening (optional)

Royal icing

• 1 cup / 140 to 145 g confectioners’ sugar
• 5 ½ teaspoons / 25 g egg whites 

Line the bottom of the pan with a disc of wax or parchment paper and grease the sides. Melt the butter and combine it with the sugar.

Stir in the flour and ground almonds.

Stir in the rum.

Add the eggs and stir until smooth.

Pour the batter into the prepared pan.

Bake at 340°F / 170°C for 45 minutes to 1 hour. The top must be a nice golden color and a cake tester inserted into the center should come out dry. Since all ovens are different, the best is to keep a careful eye on your cake as it bakes, particularly if you double the quantities.

Carefully turn the cake out of the pan onto a cooling rack.

Using a pastry brush, moisten generously with rum, if using.

The cake is good like this, but it will be even better if you store it in a cake box for three or four days. For the icing: Combine the confectioners’ sugar with the egg white and mix well.

This makes what we call royal icing.

Set the cake rack over a baking sheet lined with wax paper (so you can retrieve the icing that drips off). Pour the icing over the cake.

Let the icing flow to cover the cake. If you wish, gently shake the rack to smooth the icing.

Allow to dry for at least 1 hour. Place in a 300°F / 150°C oven for 12 minutes to set the icing to a firm texture.

At this stage, it’s best to leave the cake in a cake box for the flavors to develop, just as for the version without icing. It keeps for about 3 weeks.