In a large bowl, combine the warm water, yeast, and sugar. Allow the mixture to bubble and foam.
Next, stir in the vegetable oil and white vinegar.
Gradually add the bread flour, one cup at a time, mixing well after each addition.
Then, incorporate the kosher salt and whole wheat flour, also one cup at a time, stirring thoroughly after each addition.
The dough will be somewhat wet and spongy. Cover the bowl with a damp tea towel and let it rise in a warm area for 30 to 40 minutes, or until it has doubled in size.
Once risen, use a large spoon to transfer the dough into two well-greased loaf pans. If needed, press the sides down to shape the loaves.
Make 2 or 3 shallow diagonal cuts on the top of each loaf with a knife.
Sprinkle the tops with either steak spice for a savoury flavor or raw sugar for a sweet version.
Bake the loaves in a preheated oven at 375 degrees F for about 50 minutes, or until they are golden brown and sound hollow when tapped on the bottom.
Allow the bread to cool for at least 5 to 10 minutes before slicing.
