Preheat the oven to 180°C. Grease an 8-inch (20 cm) springform pan with nonstick cooking spray and line the bottom with parchment paper.

Fill a small pot or saucepan with about an inch of water and bring it to a simmer on the stove.

Place a heatproof bowl on top of the pot, ensuring the bottom does not touch the water.

Place chocolate into the bowl, and using a spatula, gently stir the chocolate as it melts. Ensure no water gets into the bowl, as this can cause the chocolate to seize.

Once the chocolate is melted and smooth, remove the bowl from the heat. Wipe any condensation off the bottom of the bowl before adding to the rest of the ingredients.

In a large bowl, use a hand mixer to beat the softened butter and half of the granulated sugar until light and fluffy. Add the room-temperature egg yolks one at a time, beating well after each addition.

Beat in the cooled chocolate mixture and amaretto liqueur.

Stir in the almond flour and salt until well combined.

In a separate bowl, beat the egg whites until soft peaks form. Next, add the rest of the sugar and continue mixing until stiff peaks.

Gently fold the beaten egg whites into the chocolate mixture until no white streaks remain using a rubber spatula.

Pour batter into the prepared cake pan and smooth the top with a spatula.

Bake for 40-45 minutes until the cake is set, and a toothpick inserted in the center comes out clean.

Remove the cake from the oven and let it cool on a wire rack for 10 minutes, then remove the sides of the pan and transfer the cake to a serving plate.

Dust the top of the cake with confectioners' sugar before serving.