Position a rack in the lower third of the oven and preheat the oven to 300°F. Spray the loaf pans with vegetable oil spray or line the bottom and sides with parchment paper.

In a large bowl, whisk the flour with the baking soda, baking powder, and salt to combine. Add the brown sugar, all the dried fruit, and the nuts and mix thoroughly with your fingers. Set aside.

In a small bowl, beat the eggs with the vanilla until light. Pour the egg mixture over the dry ingredients and mix well with a wooden spoon or your hands until all the fruits and nuts are coated with batter. Scrape into the prepared pan(s).

Bake until the top is deep golden brown and the batter clinging to the fruit seems set, about 1 hour for smaller loaves, 10 to 15 minutes longer for a large loaf. Tent loosely with foil if the cake appears to be browning too much. Cool completely in the pan(s) on a rack.

When completely cool, remove the cake from the pan(s). The cake keeps, wrapped airtight in foil or plastic wrap, for several weeks at room temperature or at least 3 months in the refrigerator. It can also be frozen for at least 6 months.

To serve, cut into thin slices with a sharp heavy knife.