Preheat oven to 350°F.

In a large bowl, sift together: flour, 1/2 c. sugar, baking powder, and salt together.

Whisk together all liquids, except eggs.

Mix liquid with dry; alternating.

In a stand mixer or with electric mixer, beat egg whites and cream of tartar together until they reach the soft peak stage. Then add the remaining 1/4 c. of sugar. Beat again until stiff peak stage.

Stir in about a third of the whites into the batter, then mix in the rest. Bake for 40 mins.