In a large mixing bowl, combine the melted unsalted butter, granulated sugar, and brown sugar. Blend with a hand mixer on medium speed for 2-3 minutes until light and fluffy.

Add the large eggs one at a time, mixing well after each addition. Pour in the vanilla extract and blend until smooth and evenly combined.

In a separate bowl, whisk together the all-purpose flour, cinnamon powder, cornstarch, baking soda, and baking powder. Gradually add to the wet ingredients, mixing on low speed until just incorporated.

Gently fold in the chopped toasted pecans and toffee bits ensuring they are evenly distributed throughout the dough.

Cover the mixing bowl with plastic wrap and chill the dough in the refrigerator for 30-45 minutes.

Preheat the oven to 350°F (175°C) and line a baking tray with parchment paper.

Use a cookie scoop to portion out the dough, rolling each piece into a ball. Place the cookie balls on the prepared tray, spaced about 2 inches apart.

Bake the cookies for 11-14 minutes, or until the edges are golden brown and the centers appear puffy.