Preheat oven: Preheat your oven to 170°C (338°F).

Eggs: Cold eggs can hinder the cake from rising properly. Take the eggs out of the refrigerator a few hours in advance. If short on time, submerge them in warm water for about 1 minute.

Sift dry ingredients: Sift together the cake flour and cocoa powder.

Soak fruit: Soak the dried cranberries in the rum.

Warm milk: Heat the milk in the microwave for 20 seconds.

Place the chocolate, unsalted butter, and warmed milk into a heatproof bowl. Set the bowl over a pot/container of hot water (double boiler method) to melt the mixture completely.

Once the chocolate and butter are fully melted, add the sugar and mix thoroughly.

Gradually add the beaten eggs in two additions, mixing well after each addition.

Fold in the sifted cake flour and cocoa powder using a rubber spatula, gently scooping from the bottom until just combined.

Fold in the walnuts and rum-soaked cranberries. (Toasting the walnuts in the oven for a few minutes beforehand enhances their flavor.)

Pour the batter into the prepared square baking pan and scatter the sliced almonds evenly over the top.

Place the pan on the middle rack of the oven and bake for 25 minutes.

Allow the brownie to cool completely before removing it from the pan.