In a large bowl, whip together the melted butter, white sugar, and brown sugar until it's fluffy and pale.
Incorporate the eggs and vanilla extract, blending until smooth.
Gradually add in the flour, cinnamon, cornstarch, baking soda, and baking powder. Mix until just combined.
Gently fold in the pecans and toffee bits until well mixed.
Refrigerate the dough for 30-45 minutes; this makes it easier to work with.
Scoop small portions of dough and roll them into balls, which may feel a bit crumbly at first. Warm hands help shape them well.
If desired, roll each dough ball in white sugar for extra sweetness (my mom loves this!).
Arrange them on a baking tray lined with parchment paper.
Bake in a preheated oven at 350°F for about 11-14 minutes or until the edges are golden brown. The centers will puff up and then flatten as they cool. If you want a flatter cookie, press down gently after baking. Enjoy your delightful treats!