Heat oven to 350℉/177℃.
Line sheet pans with parchment paper. Set aside.
In a medium bowl, combine flour, baking powder, and salt. Set aside.
With an electric mixer, beat butter and sugar until light and fluffy, about 2-3 minutes.
Beat in egg, egg yolk, and vanilla, scraping bowl as necessary to make sure it's well mixed.
Mix in melted chocolate.
Stir in flour mixture until just combined.
Fold in chocolate chips.
Use a 3 Tablespoon scoop to portion dough onto prepared sheet pans.
Bake 14 minutes, or until done.