In the bowl of stand mixer, combine eggs, sugar, and vanilla extract. Beat on medium until incorporated. Reduce speed to low and slowly add flour, baking powder, and salt. Scrape down sides of the bowl. Return mixer to low speed and slowly add in melted butter-chocolate mixture. Scrape down sides of the bowl and again with the mixer on low (or fold in by hand with a rubber spatula), add in chocolate chips and pecans until just combined.
Using an ice cream scoop, portion dough onto prepared baking sheets, placing about 1-1 1/2 inches apart. Bake for 10-12 minutes, until set and cooked throughout.
Allow cookies to cool for a few minutes on the baking sheet before transferring to wire racks to cool completely.
Store in an airtight container at room temperature.
This recipe calls for 9 oz. of semi-sweet baking chocolate. You can also use 1 1/2 c. (260 grams) of semi-sweet chocolate chips, if desired. The original recipe calls for chocolate chips, but I've been making these cookies with baking chocolate instead.
I used vanilla extract from our sponsor, Adams Extract in this recipe.