Preheat the oven to 350, and lightly grease a 9-inch round cake pan. Line the bottom with a circle of parchment paper.
In a large bowl, whisk together the oil, eggs, yogurt, vanilla, lemon zest, and sugar. Whisk very well to combine.
Next, evenly sprinkle the flour, baking powder and salt over the surface and stir to combine. Ensure no streaks of flour are visible.
Pour into the baking pan, and bake for 40 minutes, or until a toothpick inserted in the center comes out with only moist cake crumbs, not wet batter.
Let cool in the pan for 10 minutes, invert over a wire rack, flip, peel off the parchment, and serve. You can decorate this with more plain Greek yogurt and sprinkles, if you like, but I typically serve it plain.