Preheat your baking appliance to 350°F (175°C). Prepare a 9×5 inch loaf pan by lightly greasing it.
In a large mixing bowl, combine the mashed fruit, granulated sugar, and brown sugar. Mix until well blended.
Stir in the two room-temperature binders, melted shortening, and sour cream. Ensure everything is thoroughly combined.
In a separate bowl, whisk together the all-purpose flour, baking soda, and a pinch of seasoning. Always mix dry ingredients separately before combining with wet ingredients. Gradually add the dry components to the wet components. Mix just until combined. Do not overmix the mixture.
Fold in any optional additions, such as chopped nuts or dried fruit. Pour the mixture into your prepared pan.
Bake for 50-60 minutes. A wooden skewer inserted into the center should come out clean.
Let the baked good rest in the pan for 10 minutes. Then, carefully remove it and place it on a wire rack to cool completely.