Preheat the oven to 180°C. Grease a 9-inch round cake tin and line it with parchment paper.
In a large bowl, mix 250 grams of all-purpose flour, 1 teaspoon of baking powder, 1/2 teaspoon of baking soda, 1/4 teaspoon of salt, 1 teaspoon of cinnamon powder, and 1/2 teaspoon of nutmeg powder. Set aside.
In another bowl, soak 500 grams of mixed dried fruits (raisins, currants, sultanas, candied peels, and chopped dates) in 1/2 cup of orange juice for 30 minutes.
In a separate bowl, beat 200 grams of unsalted butter and 200 grams of powdered sugar until creamy. Add 4 eggs, one at a time, and beat well after each addition.
Gradually add the flour mixture to the butter mixture, mixing well until combined. Fold in the soaked dried fruits, 100 grams of chopped nuts (almonds, cashews, and walnuts), and 1 teaspoon of vanilla extract.
Pour the batter into the prepared cake tin and level the surface. Bake for 45-50 minutes or until a toothpick inserted in the center comes out clean.
Allow the cake to cool in the tin for 10 minutes, then transfer it to a wire rack to cool completely.