Chocolate and walnut praliné Bûche de Noël

Walnut praliné buttercream 

Walnut praliné: in a pot on medium heat, caramelise the walnuts with 125g of sugar until nicely coated, about 5 minutes). Spread them on a baking sheet and leave to cool completely. Finally, break into pieces and blitz with a mixer to turn them into a chunky powder. 

Buttercream: in a pot, mix 150g of sugar with the egg yolks, then add cornflour and warm milk. Put it on low heat and stir until the buttercream thickens. Leave to cool completely, about 2 hours, and refrigerate. Cream the softened butter and incorporate well with the cold cream. Add the walnut praliné and mix well.  
 

Now divide the mixture in two separate bowls: two thirds will remain plain to make the filling whilst one third will be mixed with dark chocolate to glaze the yule log. 

Chocolate walnut praliné buttercream: In a water bath, melt the dark chocolate and leave to cool. Mix a third of the praliné buttercream with the chocolate, and set aside. 

Sponge cake 

Preheat the oven to 200°C fan. 

Separate the egg whites from the yolks and keep both. In a bowl, beat the egg whites until soft peaks form. 
 

In another bowl, beat the sugar with the egg yolks until smooth, then add the flour and the baking powder and stir well. Finally, incorporate the beaten egg whites, then the melted butter. 

On a baking sheet or buttered parchment paper, spread the cake batter evenly to form a 25 cm square, about 1 cm high. Cook in the oven for 10 minutes, then take out and cover immediately with a sheet of parchment paper and a clean towel to lock the moisture in and prevent it from cracking. 

Leave to cool a bit until lukewarm. 

Christmas Yule log 

Take off the parchment paper and towel on top of the sponge cake. With a spatula, carefully spread the plain praliné buttercream filling evenly, then roll carefully the yule log.  

With a spatula, glaze the yule log with chocolate praliné buttercream then refrigerate for a few hours.  
 

When it’s time to serve, just take out of the fridge and sprinkle icing sugar on top.