In a food processor, grind pecans until sandlike in texture. Set aside.
Melt ½ cup butter in a sauce pot over medium heat. Continue to cook and brown the butter until fragrant. It will smell very nutty. Be careful not to burn the butter. Remove from heat.
Back to the food processor, puree cooled butter, brown sugar, and white beans together. Pour puree into the sauce pot and cook over medium heat. Stir constantly. Cook puree until it boils and because thick and gummy. This should take around 5 minutes. Remove from heat. Transfer to a bowl and let cool for 10 minutes
In a medium bowl, whisk together flour, cornstarch, and salt. Add cooled puree to dry ingredients and fold to combine.
Press dough into a 9-inch round cake pan. Lightly cover pan with plastic wrap and chill in the refrigerator for 2 hours, until dough is firm. To speed up the process, you can also freeze the dough for 30 minutes.
Preheat the oven to 325 ° F. Remove dough from the refrigerator and dock all over with a fork. Bake in the preheated oven for 30-35 minutes, until shortbread is set and lightly golden in color. Let cool. Melted chocolate chips and drizzle over cooled shortbread. Cut into wedges and serve.