Soak the wheat flour in the cultured buttermilk overnight, covered and in a warm place.
In the morning, add the sucanut, vanilla, egg yolk, lard, baking powder, and sea salt to your soaked flour. Add apples. Blend thoroughly. If your batter is thinner than cake batter usually is, add the sifted unbleached white flour until it is the right consistency.
Beat the egg white until stiff white peaks form. Fold it into the batter.
Butter a small loaf pan. Pour in the cake batter and bake at 375°F for 35 minutes, or until it is golden brown and a toothpick inserted into the center comes out clean.
While it is cooking, make the caramel sauce:
Bring all ingredients to a steady rolling boil in a medium sauce pot over medium-high heat. Keep at a steady boil for 2 minutes. Stir continually. Don’t stop stirring or it will burn!
Remove the sauce from the heat, continuing to stir until it stops boiling. Allow your caramel to cool for 5 minutes.
Once your cake is ready, pull it out of the oven and allow it to cool for 3 minutes before drizzling it with the caramel. Serve warm.