Preheat oven to 350°F. Grease a 9×13 baking dish and set aside.
In a medium bowl, whisk the flour, baking powder, baking soda, and salt together. Set aside.
Using a hand mixer or a stand mixer fitted with the paddle attachment, cream the butter with the sugar until smooth. Mix in the yogurt, milk, and vanilla extract. Add the dry ingredients to the wet ingredients and mix on low speed until combined.
Spread the batter into the prepared pan. Bake for 35-40 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow the cake to cool for 10 minutes.
Using the handle of a wooden spoon, poke holes throughout the top of the cake, being careful not to poke all the way down through the cake. Drizzle the caramel sauce evenly over the cake so that it drips into the holes. Cover and chill in the refrigerator for at least 2 hours.
To make the whipped cream:
Using a hand mixer or a stand mixer fitted with the whisk attachment, beat the heavy cream with the sugar until stiff peaks form. Spread onto chilled cake right before serving.