Preheat oven to 350 degrees. Line baking sheet with parchment paper or silicone baking mat and set aside.
In large bowl, cream butter and sugars until light and fluffy. Stir in vanilla and egg. Add in dry ingredients and stir until just incorporated.
Stir in the two kinds of chocolate chips and pecans. Scoop onto prepared baking sheets and bake 8-9 minutes or until the edges are golden and the centers look barely undercooked.
Remove from oven and cool 3 minutes. Transfer to cooling rack and serve warm. Or store in air tight container for up to 3 days.