Preheat oven to 350 degrees F. Line baking sheets with parchment paper.
In a small frying pan melt 1 tablespoon butter. Add chopped pecans and gently toast over low heat, stirring frequently. Remove from pan and set aside to cool.
In a small bowl combine 1/4 cup sugar and 1/2 cup toasted pecans. Stir well and set aside.
Using a stand mixer combine butter and sugar in mixing bowl until light, about 2 minutes.
Beat in flour, vanilla and salt, scraping down sides of bowl, just until dough comes together. Fold in pecans.
Using a 1 inch cookie scoop, roll in to a ball. Roll balls in pecan sugar mixture and set on parchment lined baking sheet. Gently flatten with bottom of glass.
Bake until golden, about 12 - 15 minutes.
Cool cookies on cooling rack.
Notes
Toast all the pecans together, then divide for the recipe and the topping.