Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper.

In a large mixing bowl, combine the melted unsalted butter, granulated sugar, and brown sugar, beating until smooth.

Add the large eggs one at a time, mixing well after each addition, then stir in vanilla extract.

In a separate bowl, whisk together all-purpose flour, cinnamon powder, cornstarch, baking soda, and baking powder.

Gradually fold the dry mixture into the wet mixture, being careful not to overmix.

Gently fold in the toasted pecans and optional toffee bits into the cookie dough.

Using a cookie scoop, drop spoonfuls of cookie dough onto prepared baking sheets, spacing at least two inches apart.

Bake for 10-12 minutes until edges are lightly golden and centers remain soft.

Let cookies cool for about 5 minutes before transferring them to a wire rack.