Preheat oven to 350° F (About 180° C). Grease and flour a 9-in (22.5 cm) springform pan. Reserve.
Melt 2 Tbsp. butter in a large skillet over medium-high heat; add the apples; sauté for 5 minutes or until softened. Remove from heat; cool completely (about 30 minutes).
Meanwhile, prepare the Streusel Topping and Caramel Sauce. Reserve 1/2 cup Caramel Sauce to drizzle the cake with just before serving.
At medium speed, beat the butter with an electric mixer until creamy; gradually add sugar, beating well. Add eggs, one at a time, beating after each addition until well blended. In a separate bowl, combine flour, baking powder, and salt. Beginning and ending with this flour mixture, add to the butter mixture alternately with the milk, beating at low speed until well blended after each addition. Stir in the vanilla.
Pour batter into the prepared pan, top with apples, drizzle with 1/2 cup Caramel Sauce; then, sprinkle with Streusel Topping.
If using a dark, coated springform pan, bake at 325° for 45 minutes (if using a noncoated shiny springform pan, bake at 350° for 45 minutes). After these 45 minutes, cover loosely with aluminum foil in order to prevent excessive browning; bake for additional 25 to 30 minutes or until center is set (note: wooden toothpick will not come out clean due to the caramel).
Cool in pan on a wire rack for 30 minutes; remove the sides of the pan. Then let cool completely on wire rack (about 1 1/2 hours). Drizzle with 1/2 cup Caramel Sauce and serve.
For the streusel: Stir together all the ingredients until blended. Let stand for 30 minutes or until firm enough to crumble into small pieces.
For the caramel sauce: In a medium saucepan over medium-high heat, bring brown sugar, butter, whipping cream, and honey to a boil , stirring constantly. Let boil, stirring constantly, for 2 minutes. Remove from heat, add the vanilla, stir, and let cool for 15 minutes before serving.
This can be stored in an airtight container in the refrigerator for up to 1 week. In order to reheat, microwave at high power for 10 to 15 seconds or just until warm; stir until smooth.
Note: Recipe based on the 'Caramel Apple Coffee Cake' recipe from Southern Living Magazine - September 2012 edition. To see the original recipe, please click on Caramel Apple Coffee Cake