Melt butter in a large skillet over medium heat. Add chopped pecans and cook, stirring occasionally, 4-5 minutes, or until lightly toasted. Set aside.

In a large bowl combine flour, cornstarch, salt, cinnamon, and baking soda; whisk well to combine then set aside.

Melt butter in a skillet over medium heat; continue cooking, stirring occasionally, until golden brown. Remove pan from heat and pour butter into a large, heatproof mixing bowl. Add in sugars and whisk well to combine. Add in vanilla. Beat in eggs, one at a time, beating until eggs are just combined.

Using a rubber spatula, fold in flour mixture, stirring until just combined. Fold in buttered pecans. Cover bowl and refrigerate at least 4 hours, up to 2 days. If you refrigerate longer than 4 hours, allow the dough sit at room temperature until it's soft.

Preheat oven to 375F. Line a large baking sheet with parchment paper. Use cookie scoop, drop rounds of dough onto prepared sheet. Firmly press a pecan half on top of each ball of cookie dough. Bake for 9 minutes, or until edges are set and the center is still a little jiggly. Sprinkle warm cookies with a little granulated sugar, if desired. Cool cookies on the pan 15 minutes, then carefully transfer to a cooling rack.