In a large mixing bowl, combine melted unsalted butter with granulated sugar and brown sugar. Beat until light and fluffy, about 2-3 minutes.

Incorporate two room-temperature eggs and a splash of pure vanilla extract into the butter-sugar mixture. Mix on low speed until smooth and creamy.

In a separate bowl, whisk together the flour, optional cinnamon, cornstarch, baking soda, and baking powder. Gradually add this to the wet ingredients, mixing until combined.

Fold in the chopped pecans and optional toffee bits until evenly distributed.

Cover the dough with plastic wrap and refrigerate for about 30-45 minutes.

Preheat your oven to 350°F (175°C). Scoop the dough and roll into balls. Optionally, roll in granulated sugar before placing on a baking sheet.

Bake for about 11-14 minutes, or until the edges are golden brown and centers are slightly underbaked.

Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.