In a large bowl, cream together the room temperature butter, ½ cup of sugar, and ¼ cup of brown sugar with a hand mixer until fluffy and creamy. Add the egg and vanilla extract, and mix until well combined. Gradually add the flour, cinnamon, baking powder, and salt, and mix until a cookie dough forms. Cover the bowl and refrigerate the dough for 1 hour.

About 10-15 minutes before taking the dough out of the fridge, peel and chop the apple into small pieces. In a small saucepan over medium-low heat, melt the 2 tbsp. butter, then add the apples, 4 tbsp. of brown sugar, and 1 tsp. of cinnamon. Stir until the mixture starts to bubble. Mix the water and cornstarch in a small bowl, then add it to the saucepan. Stir and let it simmer for 5 minutes until the filling thickens. Turn off the heat and let the filling cool for 5-10 minutes.

Preheat your oven to 350°F. While the apple filling cools, roll the cookie dough into 10 even balls. Roll each ball in ¼ cup of sugar until fully coated. Place the dough balls on a parchment-lined baking sheet, flatten them slightly with your hand, and press your finger in the center to create a deep indent.

Spoon about 1 tbsp. of the apple filling into the indent of each cookie. Bake in the preheated oven for 14 minutes, or until the cookies are golden and set. Remove from the oven and let them cool completely on a wire rack.

Once the cookies are cool, drizzle with caramel topping and sprinkle a little brown sugar on top, if desired. Serve and enjoy!