Combine apples, lemon juice, 1/4 cup sugar, and cinnamon in a small saucepan; cook over medium-high heat until boiling, then reduce heat and simmer for 10-15 minutes until apples are tender.

Dissolve cornstarch in 1 tablespoon of water, then stir into the apple mixture and cook for one minute; remove from heat and let cool.

Preheat oven to 350°F.

Using a mixer, cream softened butter and 1/2 cup granulated sugar until pale and fluffy. Beat in egg yolks and vanilla for 1 minute, then reduce speed to low and mix in flour and salt until just combined.

Roll dough into 1-inch balls, place them 1 inch apart on a cookie sheet, and press a finger or thumb into the center of each to create an indentation.

Fill each cookie indentation with about 1 teaspoon of the cooled apple pie filling, then chill the tray in the fridge for 30 minutes.

Remove from the fridge and bake the cookies on the center oven rack for 12-15 minutes until lightly golden.

Remove cookies from the oven and let them cool on the cookie sheet for 3 minutes before transferring to a cooling rack to cool completely.

Once completely cooled, drizzle cookies with store-bought or homemade caramel sauce if desired.