Drain all the soaked fruit in a large colander/sieve with a bowl underneath for about 10-15 minutes. Save the drained soaking liquid for later.
Grease a 9" springform pan with tall sides well with some butter. Then cover all sides and bottom with parchment paper. Then grease the parchment paper with more butter. Don’t skip on the parchment paper because the cake takes a long time to bake and might burn on the outside if not properly covered.
Mix together all the dry ingredients in a large bowl.
Transfer all the drained fruit into another bowl and sprinkle ¼ cup of the dry ingredients over the fruit. Toss everything together and make sure all the fruit is coated well in the flour mix.
Preheat your oven to 150C/300F for 10 minutes.
In a separate large bowl beat together the soft butter and sugar either using an electric mixer or handheld whisk, for about 2-3 minutes or until the mixture looks pale and fluffy.
Add in the eggs one at a time, whisking between each addition. Don’t worry if the mixture looks like it is curdling at this stage.
When all the eggs have been mixed well, add in the orange and lemon zest, vanilla extract, the applesauce (or grated apples) and orange juice and mix everything well together.
Now add in the dry ingredients in 2 additions and mix just until no dry clumps of flour are visible. Be careful not to overmix the batter.
Finally add in flour coated fruit mix and all the nuts into the batter and fold everything well together using a large spatula just until everything looks mixed together. The batter will be quite thick.
Transfer the cake batter it into the prepared baking pan and level the top using your spatula.
Bake for approximately 2 hours and 15 minutes. The baking time may vary depending on the type/size of your oven and the size of your baking pan(s). I kept an eye on the cake after 1 hour and 30 minutes and check it every 10 mins thereafter. When a skewer inserted into the center of the cake comes out clean, the cake is done.
Remove the cake from the oven and let it cool in the pan placed on a wire rack for about an hour. After an hour, remove the cake from the pan, peel away the parchment paper and place it back on the rack to cool completely.
Brush the cake all over with the reserved soaking liquid. Wrap the cake tightly with some parchment paper and aluminum foil. Store it until ready to serve. See notes below for storage instructions.