Yeast makes bread rise by interacting with sugars in flour to produce carbon dioxide bubbles, though the process requires kneading, heat and time for the leavening (rising) to begin before baking. Yeast breads also take longer to bake usually; however, the yeast adds considerable flavour and nutrition to the bread. Baking powder contains both an acid (cream of tartar) and a base (sodium bicarbonate) that interact with each other with the introduction of water, creating carbon dioxide bubbles that make bread rise. This reaction happens quickly and at room temperature, speeding up the baking process considerably. However, if you substitute baking powder for yeast, you may not get the results that you expect.
Preheat oven to 177 degrees Celsius.
Combine the dry ingredients, all-purpose flour, whole-wheat flour, baking powder and salt, in the large bowl and blend with a wooden spoon until thoroughly mixed.
Pour the liquid ingredients, milk, honey and vegetable oil, into the small bowl and mix well with a whisk.
Add the liquid ingredients to the dry ingredients and blend with the wooden spoon. This may produce mild foam or bubbles. Do not mix more than necessary; overmixing may force the carbon dioxide bubbles out of the dough, resulting in bread that will not rise sufficiently.
Grease the sides and bottom of the bread pan with butter.
Pour the batter into the bread pan.
Place the bread pan into the centre of the preheated oven and bake for 45 minutes or until golden brown.
Use a toothpick to check the baking progress. If any dough sticks to the toothpick, continue baking for five-minute increments and check again with a fresh toothpick; once the toothpick comes out of the bread clean, remove the loaf from the oven and cool on a wire rack.