Cookies with apple jam

Ingredients:

• 1 lb (450 g) baking apples, such as Golden Delicious, Gala, or Fuji (2-3 apples), peeled, cored, and cut into 1/4-inch (0.6 cm) cubes (about 2 1/2 cups diced apples)
• 1 tbsp lemon juice (from about half a lemon)
• 1/2 teaspoon apple pie spice
• 1/4 tsp vanilla extract
• 1 cup of sugar
• 140 g butter, room temperature
• 1 teaspoon cornstarch
• 1 and 3/4 cups premium flour
• 1/2 tsp fine salt
• 1 large egg

Preparation:

1. In a medium bowl, combine apples with lemon juice, apple pie spices, vanilla extract, and 1/3 cup sugar. Melt 2 tablespoons (30 g) butter in a medium skillet over medium heat. Add the apple mixture and toss to coat the fruit. Cover and cook, stirring occasionally and adding about 1/4 cup water if the mixture becomes too dry or starts to burn. Continue cooking until the apples are soft and shiny, about 20 minutes.
2. When the fruit is done, there should be some liquid left in the pan. If there is, add 1/4 cup water and stir. In a small bowl, combine the cornstarch with 1 teaspoon of water and pour it into the apple mixture. Stir well. Bring the mixture to a boil to activate the gelling properties of the cornstarch. Cook until thickened and bubbly (another 0.5-1 minute). Transfer the filling to a bowl and refrigerate for 15 minutes.
3. In a bowl, whisk together the flour and salt. In another bowl, beat the remaining 8 tablespoons butter with 2/3 cup sugar using an electric mixer on medium speed until fluffy, about 5 minutes. Add the egg, beating just until combined. Reduce the mixer to low speed and gradually add the dry ingredients, beating constantly. Add them in 2 additions. Beat just until combined.
4. Line two baking sheets with parchment paper. Scoop out tablespoonfuls of dough and roll them with your hands to form 2.5 cm diameter balls. Place the balls approximately 5 cm apart on the prepared baking sheets. Gently press the pad of your thumb into the center of each ball, about 1 cm deep, being careful not to crack the edges. Fill each cavity with 1 teaspoon of filling, then freeze the cookies for 15 minutes.
5. Position racks in the upper and lower thirds of the oven and preheat to 350°F (177°C).
6. Bake, rotating the baking sheets and rotating them about halfway through, until the cookies are set (about 30 minutes). Let them cool completely on the baking sheets. Can be stored in the refrigerator in an airtight container for up to 5 days..