• Preheat the oven to 350° F(175°C). Fill a cupcake tin with wrappers.

For the cake:

• Cream the butter and cream cheese until smooth. Add in the sugar, eggs, and vanilla and combine.
• In a separate bowl mix together the all dry ingredients, except for the flour. Alternately add flour and sour cream to the mixture and mix until incorporated.
• Fill each cupcake wrapper 2/3 full and bake for 18-23 minutes or until a toothpick comes out clean. Remove from the oven and transfer cupcakes to a wire rack to cool.

For the caramel sauce:

• Add the brown sugar and water into a small pot, stir until sugar dissolves. Bring to a gentle boil and cook, stirring constantly, until the mixture reaches 240° F, remove from heat.
• Add the butter, salt, and heavy cream and stir together. Let cool to room temperature. Add the rum extract. Pour half the caramel sauce into a large bowl or the bowl of a stand mixer and leave half in the pot.
• Peel and dice the apples and add to the pot. Cook until the apples are tender.

For the buttercream frosting:

• Add the butter into the bowl with the remaining caramel sauce. Beat until smooth. Slowly add in the powdered sugar in 1/2 cup increments, beating until combined between each addition. Then turn the speed on the beater up to high and whip for five minutes or until fluffy.
• Core the cupcake and fill with apple mixture. Frost with the buttercream and drizzle with caramel.