Preheat your oven to 350°F. Grease two 8-inch cake pans and set them aside.

In a large mixing bowl, combine the flour, sugar, cocoa powder, baking soda, and salt. Add the vinegar, oil, water, and vanilla extract. Mix until the batter is smooth.

Divide the batter evenly between the prepared cake pans. Bake for 25-30 minutes, or until a skewer inserted into the center comes out clean.

Let the cakes cool completely in the pans before slicing each one in half horizontally to create four layers.

To make the peanut butter nougat frosting: In a large bowl, beat the butter and peanut butter together until smooth. Gradually add the powdered sugar and vanilla extract, mixing until creamy.

To assemble the cake: Place one cake layer on a serving plate. Spread a thin layer of caramel sauce over it, followed by a quarter of the peanut butter frosting. Add another drizzle of caramel sauce on top. Repeat this process for the remaining layers.

Finish by frosting the top and sides of the cake with the remaining peanut butter frosting. Add extra caramel sauce if desired.