Preheat oven to 350 degrees. Coat 9-inch bread pan with cooking spray.
In a medium mixing bowl, combine flour, baking powder and salt. Set aside. In the bowl of stand mixer fitted with a paddle or a large mixing bowl using an electronic hand mixer, cream together yogurt, sour cream, sugar and eggs. Blend well and then add lemon zest, extract and vegetable oil. Slowly, add dry mixture. Mixture might be a little lumpy.
Pour batter into bread pan. Set pan onto a baking sheet. Bake for 55-65 minutes, or until it passes the toothpick test. If the top starts to brown before the cake is fully cooked, cover the top loosely with aluminum foil.
Remove and allow to cool for 10 minutes before gently removing from the pan. It should come out easily, but if not, cut along the sides with a knife and then tap on the bottom until it releases.
While cake is cooling, heat marmalade in a small sauce pan over low heat, whisking until smooth. Remove and stir in powdered sugar. You may need to add a little more powdered sugar or a small amount of milk or water until an easily pour-able consistency.
Glaze cake and serve. Enjoy your Lemon Yogurt "Pound" Cake!