Vanilla buttercream bûche de Noël (joconde sponge roll)

For the joconde biscuit, mix flour, sugar and almond meal; add eggs and beat on high until fluffy; add the melted butter and transfer to a separate bowl.

Whip the egg white with a third of the granulated sugar on high, adding the rest of the sugar, until stiff.

Carefully incorporate the meringue into the almond mixture without overworking so it does not deflate.

Stick parchment to an upside-down baking sheet with a dot of butter at each corner, spread the batter evenly, and bake in a preheated 450 F / 230 C oven for about 7 minutes.

Cover with parchment, flip the biscuit onto a clean kitchen towel and let cool; prepare the simple syrup.

Bring milk, sugar and vanilla to a boil; beat egg yolks and sugar in a separate bowl.

Off the heat, whisk a third of the milk into the yolks, then gradually the rest, whisking constantly.

Return the custard to the stove and heat gently to just below boiling, 185 F / 85 C.

When the custard is at room temperature, add the softened butter and whip on high until creamy and fluffy.

Lay the biscuit skin side up, moisten with vanilla simple syrup, spread about half the buttercream and roll into a cylinder.

Brush more syrup on the log, tighten it with a wire rack, baking tray or rectangle dish, and freeze or refrigerate until firm.

Trim the ends, frost the log with the remaining buttercream using a star tip or spatula, and draw a fork along it to make a bark pattern.