In an extra-large bowl, combine the pecans, raisins, pineapple, and cherries. Take a small handful of the measured flour and toss with the fruit/nut mixture until well dredged.
In a stand mixer, cream the butter and sugar until incredibly fluffy and absolutely no grit remains when rubbed between your fingers.
Add the 6 beaten egg yolks to the butter mixture and beat well.
Whisk the remaining flour and baking powder together. Add to the butter mixture, followed by the lemon extract. Beat until smooth.
Remove the bowl from the mixer. Using a heavy spoon, manually fold the flour-dredged fruit and nuts into the thick batter.
In a separate clean bowl, beat the 6 egg whites until stiff peaks form. Gently fold the egg whites into the heavy batter as the final step.
Preheat oven to 250°F. Grease and flour two large tube pans (or a combination of tube and loaf pans).
Pour the batter into the prepared pans. Bake for 3 hours at 250°F, or until a long skewer inserted into the center comes out clean.
Cool completely before removing from pans. Store in a tight container for several days or weeks to age.