Dissolve the yeast in warm water in a large bowl. Stir in 1 tbsp of the sugar and wait for the yeast to start bubbling.
Add the remaining sugar, salt, oil and 3 cups flour. Using a dough hook attached to your stand mixer, beat the dough until smooth.
Stir in enough remaining flour, 1/2 cup at a time, to form a soft dough that only slightly sticks to your hands. Let the dough hook knead the dough for another 4-5 minutes until the dough is smooth and elastic.
Alternatively if you don't have a mixer, turn the dough out onto a floured surface and then knead until smooth and elastic, around 8-10 minutes.
Place the dough in a greased bowl, turning the dough around to grease all sides to prevent it from drying.Cover with a clean tea towel and let rise in a warm place until doubled, about 1-1/2 hours.
Punch the dough down. Turn the dough out onto a lightly floured surface; divide dough in half. Shape each piece of dough into a loaf.
Place in 2 greased 9x5-in. loaf pans. Cover again and let rise in a warm place until doubled, 30-45 minutes.
Bake the loaves in the oven at 375° for 30-35 minutes or until golden brown and bread sounds hollow when tapped. You can also use an instant thermometer to see if the bread has reached 200 °F in the middle, meaning it's done.