Mix the ingredients. Add the flour, buttermilk, water, vegetable oil, sugar, egg, salt, and yeast in the stand mixer bowl fitted with a dough hook or a large mixing bowl. Mix at low speed (or stir by hand) for 2-3 minutes until dough forms. The dough should come together and not stick to the sides or bottom of the bowl.
Knead the dough. Knead the dough on medium speed in the mixer (or knead by hand on a lightly floured surface) for 10-15 minutes until the dough is smooth, soft, and elastic. The dough is ready when it passes the “windowpane test”—if you stretch a piece of dough between your fingers, it should become thin and translucent without tearing. If the dough feels dry, add a teaspoon of water until moist but not sticky. If it’s too sticky, sprinkle in a little flour.
The first rise. Shape the dough into a smooth ball and place it in a clean, lightly oiled bowl. Then, cover the bowl with a clean, damp tea towel or plastic wrap and place it in a warm spot. Let the dough rise for about 60 minutes until it has doubled and looks puffy.
Shape into a loaf. Lightly grease a 9x5-inch loaf pan with nonstick spray. Turn the risen dough out onto a lightly floured surface. Then, gently stretch the dough into a rectangle, making the shorter side the same length as the longer side of the loaf pan (about 9x18 inches). Next, fold the top edges and start rolling the dough down, keeping it tight. Tuck the ends under and pinch the seam closed. Place the loaf, seam-side down, into the prepared loaf pan.
The second rise. Cover the loaf with heavily greased plastic wrap or a clean towel. Let it rise in a warm place for 45-60 minutes or until the dough has risen about 1 inch above the edge of the pan. Towards the end of the rising time, preheat your oven to 350°F (175°C).
Bake. Brush the top of the loaf with melted butter. Bake the loaf in the preheated oven for 35-40 minutes, or until the top is golden brown and the bread sounds hollow when tapped. If you have an instant-read thermometer, the internal temperature should reach 195-200°F (90-93°C).
Cool. Remove the bread from the oven and carefully turn it from the pan onto a wire rack. Let it cool completely before slicing.