Heat the oven to 175 C / 350 F. Grease a 9x13 inch quarter sheet pan and line it with parchment paper.

Whisk together cake flour, almond flour, baking powder, and salt in a bowl. Set aside.

Beat softened butter and granulated sugar in a stand mixer on medium speed for 3 to 4 minutes until pale and fluffy.

Add eggs one at a time, mixing on medium after each addition until fully incorporated. Scrape down the bowl between additions.

Add the scraped vanilla bean seeds and mix for 10 seconds.

Reduce mixer to low. Add the flour mixture in three additions, alternating with the milk in two additions. Start and end with flour. Mix only until just combined.

Spread the batter evenly in the prepared pan using an offset spatula.

Bake for 20 to 25 minutes until the top is golden and a toothpick inserted in the center comes out clean.

Cool in the pan for 10 minutes, then turn out onto a wire rack and cool completely, at least 1 hour.

Beat softened butter in the stand mixer on medium-high for 2 minutes until smooth.

Add sifted powdered sugar in two additions, mixing on low to combine, then raising to medium until fluffy.

Add scraped vanilla bean seeds, heavy cream, and a pinch of salt. Beat for 1 minute until light and spreadable.

Once the sponge is completely cool, use a long serrated knife to slice it horizontally into two even layers.

Place the bottom layer on a parchment-lined sheet pan. Brush the surface with a thin coat of strained warm apricot jam.

Spread the vanilla buttercream evenly over the jam layer using an offset spatula, about 4 mm thick.

Brush the cut side of the top sponge layer with apricot jam, then lay it jam-side down onto the buttercream.

Press gently to bond the layers, then brush the top surface with a thin coat of apricot jam.

Wrap the layered block tightly in plastic wrap and refrigerate for at least 2 hours, or overnight.

Remove the chilled sponge block from the fridge. Using a sharp knife, trim the edges to straighten them, then cut into 3 cm x 3 cm cubes, wiping the blade clean between cuts.

Place the cubes on a wire rack set over a parchment-lined sheet pan, spaced about 2 cm apart.

Warm the poured fondant in a heatproof bowl over a pot of simmering water, stirring until it reaches 38 C / 100 F. Add warm water one teaspoon at a time if it seems too thick to pour.

Working quickly, spoon fondant over each cube until all sides are coated. Use a small offset spatula to smooth any drips around the base.

Decorate immediately with a sugar pearl or small edible decoration before the fondant sets.

Leave at room temperature for 30 to 45 minutes until the fondant sets to a smooth, firm shell. Transfer to a serving plate or storage container.