Cream together the melted butter, granulated sugar, and brown sugar until light and fluffy.

Add the egg and vanilla extract, mixing until fully combined.

In a separate bowl, whisk together flour, cornstarch, baking soda, baking powder, and cinnamon, then combine with wet ingredients.

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

Chill the dough in the refrigerator for 30 to 45 minutes.

Scoop the dough and form balls, placing them on a baking sheet spaced apart.

Bake in a preheated oven for 11 to 14 minutes, until edges are golden brown.

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