In a large bowl or stand mixer bowl, combine warm water and 2 tablespoons of the sugar. Sprinkle yeast over the surface and let sit until foamy and fragrant, about 5-10 minutes. If it doesn't foam, your yeast is dead - start over with fresh yeast.

Add remaining sugar, vegetable oil, and salt to the yeast mixture. Stir to combine. Add 5 cups of flour and mix on low speed (or stir with a wooden spoon) until a shaggy dough forms.

Continue kneading on medium-low speed for 8-10 minutes, or turn out onto a floured surface and knead by hand for 10-12 minutes, adding remaining flour 1/4 cup at a time as needed. The dough should be smooth, elastic, and slightly tacky but not sticky - it should spring back when poked.

Lightly oil a large bowl, place dough inside, and turn to coat. Cover with a clean kitchen towel and let rise in a warm, draft-free spot until doubled in size, about 1 hour. Press two fingers into the dough - if the indent remains, it's ready.

Gently punch down the dough to release air. Turn onto a lightly floured surface and divide in half. Pat each portion into a rectangle about 9 inches wide, then roll tightly from the short end, pinching the seam to seal. Tuck ends under and place seam-side down in greased 9x5-inch loaf pans.

Cover loosely with the towel and let rise until dough crowns 1 inch above the rim of the pans, about 30-45 minutes. Preheat oven to 350 degrees F during the last 15 minutes of rising.

Bake for 30-35 minutes until deep golden brown and the internal temperature reaches 190 degrees F. Immediately remove from pans and brush tops with melted butter. Cool completely on a wire rack before slicing, at least 2 hours - cutting too early ruins the texture.