In the bowl of a stand mixer, combine the warm water, sugar, and yeast and let the yeast proof for 3 to 5 minutes until foamy (unless using instant yeast, in which case you don't need to wait for it to bubble and foam).
Add the salt, oil, and 3 cups of the flour to the yeast mixture and mix using the dough hook attachment for a minute or two, just until it starts to combine. Add in the remaining 2 ½ to 3 cups of flour about half a cup at a time while the mixer is running, just until the dough forms into a ball that starts to come away from the sides of the bowl and doesn't leave a lot of sticky residue on your fingers when you touch it. Continue to knead the dough for 2-3 minutes until smooth, adding a little more flour if the dough starts to stick to the sides of the bowl again. Let the dough rest for 5 minutes, then knead again for another 1-2 minutes.
Transfer the dough to a large, lightly greased bowl and cover it with a kitchen towel or a piece of plastic wrap sprayed lightly with cooking spray. Let the dough rise in a warm place until doubled in size, about an hour.
When the dough has risen, turn it out onto a clean counter that has been lightly sprayed with cooking spray and divide the dough into two equal sections. Working with one half of the dough at a time, pat it into a large rectangle, roughly 9x13-inches.
Roll the dough up starting from the long edges into a tight cylinder, turning the ends under and pinching the edges together to seal, then placing the loaf seam side down on a french bread pan or baking sheet lined with parchment paper or a silpat mat. Repeat with the remaining dough to form the second loaf, using a separate pan or making sure the baking sheet you are using is large enough that the loaves won't touch as they rise and bake.
Cover the loaves with a kitchen towel or a piece of plastic wrap sprayed lightly with cooking spray and let them rise again a warm place for another 30-45 minutes, until nearly doubled again in size.
When the loaves are close to being fully risen, preheat the oven to 375 degrees F. Just before putting the loaves in the oven, cut several gashes on an angle about 2-inches apart along the top of each loaf using a very sharp knife or baker's lame. If you like a crispy crust, brush each loaf before baking with an egg wash made with 1 egg white beaten with 1 teaspoon of water.
Transfer the loaves to the oven and toss 3-4 ice cubes right onto the bottom of the oven floor and immediately close the oven door. The moisture trapped in the oven from the evaporating ice cubes will help create the classic crust that french bread is known for. If you are using two baking sheets and don't have room to cook both loaves at the same time, wait to cut gashes in the top of the second loaf until after the first loaf has baked.
Bake for 25-30 minutes until golden brown. Brush loaves with melted butter after removing from the oven, if desired.