In a mixing bowl, combine the melted butter, granulated sugar, and brown sugar. Cream until light and fluffy, about 2-3 minutes. Add room-temperature eggs one at a time, then stir in the vanilla extract.

Gradually incorporate the dry ingredients into the wet mixture. Whisk together all-purpose flour, cornstarch, baking soda, baking powder, and cinnamon in a separate bowl and add to the wet ingredients.

Gently fold in the chopped, toasted pecans and optional toffee bits.

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

Preheat the oven to 350°F (175°C). Roll the dough into small balls, about a tablespoon in size, and place them on a parchment-lined baking tray.

Bake for 11-14 minutes until the edges are golden and centers are slightly soft.

Let the cookies cool on the tray for 5 minutes before transferring them to a wire rack.