In a large bowl, whisk together the flour, salt, sugar and instant yeast. Add the water, followed by the oil. Using a rubber spatula, mix until the liquid is absorbed and the ingredients form a sticky dough ball. Cover the bowl with a damp tea towel or plastic wrap and set aside in a warm spot to rise for 1 1/2 to 2 hours, until the dough has doubled in bulk.

Set a rack in the middle of the oven and preheat it to 375 degrees. Grease two 8.5- by 4.5-inch loaf pans generously with the softened butter. Using 2 forks, deflate the dough by releasing it from the sides of the bowl and pulling it toward the center. Rotate the bowl quarter-turns as you deflate, turning the mass into a rough ball.

Using your 2 forks and working from the center out, separate the dough into 2 equal pieces. With greased hands, lift each half of dough into a prepared pan. Do not cover the pans. Let the dough rise on the countertop near the oven (or another warm, draft-free spot) for 20 to 25 minutes, until the top of the dough just crowns the rims of the pans.

Transfer the pans to the oven and bake for 40 to 45 minutes, until the tops are golden brown and firm to touch. Remove the pans from the oven and turn the loaves out onto a cooling rack. Let them rest on their sides for at least 15 minutes before cutting.

*If it offends your moral fibers to make bread without any whole-wheat flour, 1 to 2 cups of whole-wheat flour can be substituted here.