In a large mixing bowl, combine the active sourdough starter and warm water. Stir gently to mix.
Add the all-purpose flour and salt to the bowl. Mix with a wooden spoon or spatula until a shaggy, sticky dough forms and all flour is incorporated.
Cover the bowl with plastic wrap or a clean kitchen towel. Let the dough rest at room temperature for 12 hours, or overnight, until it has doubled in size and is bubbly.
After the dough has risen, lightly oil a standard 9×5 inch loaf pan with olive oil.
Using a spatula or wet hands, gently transfer the dough into the prepared loaf pan, spreading it evenly but without deflating it too much.
Cover the loaf pan loosely with plastic wrap or a kitchen towel and let it proof at room temperature for 1 to 2 hours, until it has risen about 1 inch above the rim of the pan.
Preheat your oven to 450°F (230°C) with a rack in the middle position.
Once preheated, place the loaf pan in the oven and bake for 40 to 50 minutes, until the crust is deep golden brown and the internal temperature of the bread reaches 205°F (96°C).
Remove the bread from the oven and carefully transfer it from the pan to a wire rack. Let it cool completely, about 1 to 2 hours, before slicing.