Stir yeast, warm water, sugar, oil, and salt in large bowl until dissolved.
Separately mix flour and salt.
Add flour and salt to yeast mixture and mix well, then knead until formed into a ball.
Place dough ball into a large bowl sprayed with cooking spray. Cover with saran wrap and let rise for 20-30 minutes until doubled in size.
Separate into 2 circular loaves and place on cookie sheet sprayed with cooking oil.
Cover and let rise 30-40 minutes, or until doubled.
Preheat oven to 425°F.
Lightly score the top of the dough loaves with 1-3 slices.
Bake at 425 for 10 minutes; WITHOUT opening oven door, turn to 375°F and bake for an additional 25-30 minutes until loaves are a deep golden brown color (if they aren't a deep enough brown, they won't be cooked enough in the middle).
Once they are deep golden brown, remove from oven and brush generously with salted butter.
If desired, sprinkle with coarse flake sea salt, if desired.
Let cool for 5 minutes, then slice with a bread knife.