In a large mixing bowl, combine the warm water, honey (or sugar), and sourdough starter. Stir until the honey dissolves and the mixture is smooth.

Gradually add the flour, salt, and instant yeast (if using). Stir with a wooden spoon or dough hook until the mixture forms a dough.

Add the olive oil (or butter) and knead for 8-10 minutes until the dough is smooth and elastic.

Shape the dough into a ball and place it in a lightly greased bowl. Cover with a towel or plastic wrap and let it rise for 4-6 hours, or until doubled in size.

Punch down the dough, then transfer it to a floured surface. Shape it into a loaf by folding the edges and rolling it tightly.

Place the shaped dough into a greased 9×5-inch loaf pan. Cover again and let it rise for 1-2 hours, or until slightly above the pan’s top.

Preheat the oven to 375°F (190°C). Bake the bread for 30-35 minutes, or until golden brown and the loaf sounds hollow when tapped on the bottom.

Cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.