To prep for the apples, toss chopped apples with 1 tbsp brown sugar + ½ tsp cinnamon. Set aside.
In a large bowl, whisk melted butter and sugars until glossy. Add egg, yolk, and whisk until smooth. Stir in vanilla.
In another bowl, whisk 1 3/4 cup flour, 1 1/2 cup oats, 1/2 tsp baking soda, 1/2 tsp baking powder, spices, and salt.
Stir dry ingredients into wet until just combined. Fold in about 1 cup of the apple mixture.
Cover and refrigerate for at least 30 minutes (up to overnight).
Preheat oven to 350°F. Scoop dough to your desired size (I made mine fairly large, it made 16 large cookies) roll into balls, and place onto parchment-lined baking sheets.
Bake for 11–13 minutes, until edges are golden but centers look soft. Let sit on pan 5 minutes before moving.
Glaze (optional): Whisk powdered sugar, maple extract, cream, and salt until drizzle-consistency. Drizzle over cooled cookies.