Cream the melted butter with granulated and brown sugars using an electric mixer on medium speed for about 2 minutes until fluffy and light in color.

Add in the eggs and vanilla extract, mixing on low speed until smooth, approximately 30 seconds.

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

Fold in the chopped pecans and toffee bits gently with a spatula.

Cover the bowl with plastic wrap and chill in the refrigerator for 30 to 45 minutes.

Preheat the oven to 350°F (175°C) and line baking sheets with parchment paper. Scoop tablespoon-sized dough onto the sheets, leaving space in between.

Bake for 11 to 14 minutes until the edges are golden brown and the centers appear slightly puffy.

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