Preheat the oven to 350°F. Line a baking sheet with parchment paper.

Combine melted butter and chopped pecans in a bowl and toss to coat.

Spread the pecans evenly on the baking sheet and toast for 5-7 minutes until fragrant.

Allow pecans to cool. In a mixing bowl, cream together butter and brown sugar until fluffy.

Add vanilla and egg to the creamed mixture and beat well.

In a separate bowl, whisk together flour, baking soda, cornstarch, and salt.

Gradually add dry ingredients to wet ingredients, mixing until combined.

Stir in cooled toasted pecans.

Form cookie dough into 2-tablespoon balls and place on prepared baking sheet.

Bake for 12 minutes until edges are golden. Allow cookies to cool on sheet for 3 minutes, then transfer to wire rack.