This step is optional - Heat a pan over high heat, when pan is hot, add pecans, lower heat and stir and toast pecans for a couple of minutes until it is slightly browned. Set aside to cool.
Preheat oven to 350°F.
Grease baking sheets with butter or use parchment paper.
Whisk flour, baking soda, salt and coffee powder in a bowl; set aside.
Using a stand mixer with a paddle attachment or a hand mixer, cream butter and sugar until light and fluffy.
Add in eggs, one at a time, beat well after each addition then add the vanilla. Mix well.
Gradually tap in the flour mixture at low speed. Mix until well incorporated.
Fold in the chocolate chunks and pecan pieces using silicon spatula.
Scoop cookie dough using a small ice cream scoop, 2 inches apart onto baking sheets.
Bake for 9-10 minutes or until the edges are set and slighly browned.
Serve warm with milk or coffee.