Preheat oven to 350°F (175°C). Spread pecans on a baking sheet and toast for 8–10 minutes, stirring once, until fragrant. Cool, then chop.

In a bowl, whisk together oats, flour, baking soda, salt, and cinnamon.

In a large bowl, stir together melted butter, brown sugar, and granulated sugar until smooth and glossy. Add egg, egg yolk, vanilla, and maple syrup; mix until fully combined.

Add dry ingredients to wet and stir just until no dry streaks remain. Fold in chopped pecans and optional ingredients if using.

Cover and chill dough for 30–60 minutes for thicker, chewier cookies.

Line baking sheets with parchment. Scoop 2-tablespoon mounds (about 40 g each) spaced 2–3 inches apart.

Bake at 350°F (175°C) for 10–12 minutes until edges are set and centers look slightly soft.

Cool on the pan for 5 minutes, then transfer to a rack to finish setting.