Add the dry ingredients to the wet ingredients, stirring just until just incorporated; batter will be very thick. Do not over mix! Lastly, gently fold in the apples by hand. Transfer the cake batter into a greased 9x13 cake pan, spreading it out evenly.
3 cups peeled and diced apples (3-4 large tart or semi-tart apples, such as Granny Smith, Jonathon, Honey Crisp, McIntosh, or Pink Lady)
Bake the cake, uncovered, on the center oven rack for 45-55 minutes, or until a cake tester inserted into the center of the cake comes out clean. Cool completely before adding the topping.
Make the Caramel Sauce
In a saucepan, over medium heat, combine the butter, brown sugar, salt. and cream. Cook, whisking constantly, just until the mixture boils; let the caramel sauce gently boil for 3 minutes without whisking. Remove the sauce from the heat, immediately pouring it over the top of the cooled cake. Let the sauced cake sit for an hour before serving.
1/3 cup butter, 3/4 cup dark brown sugar, 1/2 teaspoon kosher salt, 3 tablespoons heavy cream or half-and-half
Serve the Cake
Slice the cake into serving pieces. Serve topped with a dollop or squirt of whipped topping, as desired.