TO MAKE THE CAKE:
Preheat oven to 350°F and spray a 9-inch cake pan with baking spray and line the bottom with parchment paper, set aside.
In a bowl whisk together flour, baking powder, and salt, set aside.
In another bowl whisk together sugar, yogurt, oil, eggs, and vanilla.
Gradually whisk the dry into the wet ingredients until there are no visible bits of flour and the batter is mostly smooth.
Pour batter into prepared cake pan and bake for 35 to 40 minutes or until a toothpick inserted comes out mostly clean with a few moist (not wet) crumbs.
Let cake cool in the pan for 10 minutes in the pan before inverting onto a wire rack to cool completely.
If you want a flat cake, use a serrated knife to cut the cake top off.
TO MAKE THE FROSTING:
In a large bowl, beat cream cheese until smooth and lump free, about 2 to 3 minutes on a medium speed.
Change to a whisk attachment and gradually add yogurt, powdered sugar, and vanilla, whipping until smooth.
Spread on top of cooled cake and garnish or serve with berries if desired.