• Preheat oven to 350°F.  Grease the bottom of an 8 ½ by 4 ¼ loaf pan.  Line the bottom with parchment paper, then grease and flour the entire pan.  Set aside.
• Sift together the flour, baking powder and salt onto a large of wax paper.  Set aside.  In a large bowl whisk together the yogurt, 1 cup of granulated sugar, the eggs, lemon zest and vanilla.  Slowly whisk in the flour mixture a little at a time until blended.  Using a rubber spatula, fold in the vegetable oil until well incorporated.  Pour the batter into the prepared pan and bake for 50 minutes or until a toothpick tested in the center comes out clean.
• While the cake is baking cook the remaining ⅓ cup granulated sugar and ⅓ cup lemon juice in a small pan until the sugar dissolves and the mixture is clear.  Set aside.
• When the cake is done, allow it to cool in the pan for 10 minutes.  Carefully place the bake on a baking rack set over a piece of wax paper (I used the one that held the flour mixture after sifting.)  While the cake is still warm, pour the lemon-sugar glaze over the cake and allow it to soak in.  Cool completely.

To make the glaze:

• Combine the confectioners' sugar and lemon juice and pour over the cake.
• Slice and serve.