For the cupcakes: Preheat oven to 350 degrees Fahrenheit. Line cupcake pan with paper cups.
In a large bowl, whisk together the flour, baking powder, ground cinnamon, apple pie spice, and salt.
In a large microwave-safe bowl, melt butter in the microwave in 20 second increments until melted. Whisk in sugar. Mix in eggs one at a time until well mixed. Pour in vanilla, buttermilk, and yogurt until combined. Slowly stir in dry ingredients until no lumps remain. Batter will be thick.
Divide batter among cupcake liners, filling each ⅔ full.
Bake in preheated oven for about 17 to 19 minutes or when a toothpick inserted into center comes out clean. Remove from oven and allow to cool in muffin tin several minutes before transferring to a wire rack. Allow to cool completely before filling and frosting.
Make the apple pie filling: In a medium saucepan, place chopped apples, butter, brown sugar, lemon juice, cinnamon, and apple pie spice together. Cook over medium heat for about 5 to 8 minutes, until apples are tender. Stir occasionally. Allow mixture to cool.
Make the frosting: In the bowl of an electric stand mixer or with your hand mixer, cream butter on medium high speed for about 3 to 4 minutes. Add vanilla extract and salted caramel sauce; mix until combined, scraping down the sides as needed.
Add 1 cup of powdered sugar and salt; beat on low until powdered sugar is incorporated. Add heavy cream and then add more powdered sugar until desired consistency is achieved.
Increase speed to medium, and beat until smooth and well combined for another 2 minutes. Scrape down the sides and bottom of the bowl as needed.
Prepare a piping bag and fill with frosting.
Assembly: Using a small knife, cut and remove a circle in the center of each cupcake.
Fill with apple filling.
Pour a layer of salted caramel over the apples.
Pipe frosting on top. ( I used a Wilton 1M tip )
Drizzle with more salted caramel sauce and add optional toppings if desired.