1. 1. In a skillet over medium heat, combine the diced Gala apples, dark brown sugar, ground cinnamon, salt, and lemon juice. Cook until softened and caramelized, about 8-10 minutes. Allow to cool.

2. 2. Melt the unsalted butter in a saucepan over medium heat, stirring constantly until it turns a rich, nutty brown color, about 5-7 minutes. Let cool slightly.

3. 3. In a large bowl, combine the browned butter, dark brown sugar, and granulated sugar. Beat in vanilla, egg, and egg yolk until smooth.

4. 4. In another bowl, whisk together flour, baking soda, cream of tartar, ground cinnamon, salt, and cornstarch. Gradually mix into wet ingredients until just combined. Fold in cooled caramelized apples.

5. 5. Cover and chill dough in the refrigerator for at least 30 minutes.

6. 6. Preheat oven to 350°F. Line baking sheets with parchment paper. Mix granulated sugar and ground cinnamon for coating.

7. 7. Scoop chilled dough into balls (about 1.5 tablespoon each), roll in cinnamon-sugar mixture, and place on baking sheets spaced 2 inches apart.

8. 8. Bake for 12-15 minutes until edges are golden but centers remain soft. Cool on baking sheets for 5 minutes before transferring to wire racks.