Preheat oven to 350°F with a rack in the center of the oven.
In a large bowl whisk sugar, yogurt, oil, eggs, vanilla, and lemon/orange zest.
In a separate bowl combine flour, almond flour (if using), baking powder, baking soda, and salt. Add the dry ingredients to the wet ingredients, whisking until combined.
Pour into a greased 9x5 loaf pan (I prefer metal over glass). Bake for about 40-55 minutes. This is a fairly large time range because ovens vary in temperature and the pan that you use can affect bake time. Tent the loaf with foil after about 30 minutes to keep the top from getting too dark. The cake is done when a toothpick inserted into the center comes out clean. Be sure not to overbake. Cool cake in the pan set on a wire rack for at least 30 minutes before removing from the pan.
