Preheat oven to 350F degrees. Line the bottom of 8 1/2 by 4 1/4 by 2 1/2 - inch loaf pan with parchment paper. Grease with nonstick cooking spray WITH FLOUR IN IT (or grease and flour pan).
Lemon Loaf: In a medium bowl, sift together the flour, baking powder, and salt. In a separate large bowl, whisk together the sour cream, sugar, eggs, lemon extract, lemon zest, and vanilla. Slowly whisk the dry ingredients into the wet ingredients. With a rubber spatula, fold the vegetable oil into the batter until its fully incorporated without overmixing.
Pour the batter into the prepared pan and bake for approximately 50 minutes, or until a cake tester placed in the center of the loaf comes out clean, adding foil to cover the top of the loaf the last 10 minutes of baking if necessary.
When the cake is done, allow it to cool in the pan for 10 minutes then carefully transfer to a baking rack over a sheet pan (for easy clean up after cream cheese drizzle).
Lemon Syrup: Meanwhile, while cake is cooling, cook 1/4 cup lemon juice and 1/3 cup sugar in a small pan until the sugar dissolves and the mixture is clear. While the cake is still warm, poke holes or slits all over the loaf and pour this Lemon Syrup over the cake and allow it to soak in.
Cream Cheese Lemon Glaze: In a large mixing bowl, beat cream cheese until soft and very creamy. Beat in 1 cup plus 2 tablespoons confectioners' sugar, lemon juice and lemon extract. Taste and add additional sugar if you like a sweeter glaze. If you want a thinner glaze, mix in additional lemon juice or milk if desired. I like to pour a layer of Glaze all over the cake, let it set then drizzle another layer then use the remaining glaze on individual slices OR you can drizzle Glaze all over the cake. Enjoy!