Walnut Meringue Cake

Beat the softened butter with sugar until pale and fluffy, then mix in the egg yolks and sour cream.

Fold in the flour and baking powder using a spatula to form a soft dough.

Draw 18 cm circles on parchment paper and flip them pencil-side down. Divide the dough into 4 equal portions.

Spoon the dough onto the circles, dust with a bit of flour, and gently press it out to fill the shapes. Top with half of the ground walnuts.

For the meringue, whip the egg whites and sugar together until stiff, glossy peaks form.

Spread the meringue evenly over the dough layers and sprinkle with the remaining walnuts.

Bake at 150°C (300°F) with convection for 25 minutes, making sure to leave plenty of space between the layers for airflow.

For the frosting, beat the softened butter until pale, add the boiled condensed milk, and whip again until smooth.