Preheat the oven to 325°F (160°C). Line a 9x5-inch loaf pan with greased parchment paper, allowing the edges to extend above the rim for easy removal after baking.

In a small bowl, mix the sour cream with baking soda and set aside. This mixture will activate and help the cake achieve a light texture.

In a separate bowl, combine the raisins, dates, cherries, and walnuts with ¼ cup (30g) of the flour. Toss until all pieces are well coated to prevent them from sinking during baking.

In a large mixing bowl, cream together the butter and sugar until light and fluffy. Add the egg and beat until fully incorporated. Mix in the orange zest, followed by the sour cream and baking soda mixture.

Gradually add the remaining 1¾ cups (230g) of flour along with the salt, mixing until smooth. Gently fold in the flour-coated fruit and nut mixture until evenly distributed throughout the batter.

Transfer the batter into the prepared loaf pan, pressing down to even the surface. For best results, place a shallow pan of water on the rack below the cake to ensure even baking and moisture retention.

Bake for 1½ to 1¾ hours, or until a wooden skewer inserted into the center comes out clean and the internal temperature reaches 205–209°F (96–98°C). If the top browns too quickly, cover loosely with foil during baking.

Remove from the oven and allow the cake to cool for 5 minutes in the pan. Then lift it out using the parchment edges and transfer to a wire rack to cool completely.

If desired, poke small holes in the top of the cooled cake with a skewer and drizzle with brandy for additional moisture and flavor. Wrap tightly in plastic wrap followed by aluminum foil for storage.