Make the apple filling

In a large skillet over medium heat, combine butter, diced apples, brown sugar, and cinnamon.

Stir often as the butter melts and the sugar fully dissolves. When the mixture begins to simmer (bubbling slightly), reduce heat if it’s splattering.

Continue cooking for about 5 to 10 minutes, until apples soften but still hold a slight bite (not mushy).

In a small bowl, stir together cornstarch and cool water until smooth.

Pour the cornstarch slurry into the pan, stirring constantly. Cook for an additional 30–60 seconds until the mixture thickens into a glossy sauce.

Remove from heat and transfer to a heatproof bowl. Let the filling cool fully to room temperature before using it in cookies.

2. Prepare the cookie dough

Preheat your oven to 350 °F (about 175 °C). Line one or more large baking sheets with parchment paper.

In a medium bowl, whisk together flour, cinnamon, baking powder, and salt. Set aside.

In a large mixing bowl, cream together butter and brown sugar (using an electric mixer or by hand) until light and fluffy, about 2–3 minutes.

Add the egg, egg yolk, and vanilla extract, and mix until combined. The mixture may look a little grainy—that’s okay.

Gradually fold in the dry ingredients, mixing until no dry streaks remain. Don’t overmix; stop once fully incorporated.

3. Coat dough and shape cookies

In a shallow bowl, combine granulated sugar and cinnamon to make your cinnamon sugar coating.

Using a 3‑tablespoon cookie scoop (or dry measuring spoon), portion out balls of dough (~3 tbsp each). Roll each ball in the cinnamon sugar mixture until fully coated.

Place 5 to 6 cookies per baking sheet, leaving about 3 inches (7–8 cm) between each to allow for spreading.

Use a measuring teaspoon or your thumb to press a shallow indentation into the center of each cookie (~½ inch deep).

Fill each indentation with about 1 teaspoon of the cooled apple filling (don’t overfill or it may leak).

4. Bake & cool

Bake in the center of the preheated 350 °F oven for 10–12 minutes, or until the edges turn golden brown.

Let the cookies cool on the baking sheet for about 5 minutes (this helps them set), then transfer them to a wire rack to cool completely.

Be sure your baking sheet has cooled fully before starting the next batch.

Optional: once cool, drizzle with caramel sauce or a dusting of powdered sugar if desired.