Line two cookies sheets with parchment paper or use silicone baking mats.
In a medium bowl, use a mixer to beat the butter and sugars until smooth.
Add eggs one at a time. Beat in vanilla.
In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
Add the dry ingredients to the wet ingredients one cup at a time until well combined.
Stir in chocolate chips and pecans.
Place dough in the freezer for 20 to 30 minutes. This is an important step, so don't skip it. Your cookies will spread a lot more if you don't chill the dough first.
As soon as the dough is out of the freezer, use your hands to make 30 rounded mounds of dough, spacing about 2 inches on the cookies sheets. (Do not press them down).
Bake cookies for 16 to 18 minutes or until cookies turn light brown on top and crisp around the edges.
Rotate cookie sheets halfway through baking time. Let cool for five minutes on cookie sheets. Cool completely on a wire rack or enjoy them warm right away.