Preheat oven to 350°F. Lightly grease or line 2 (9-inch round) cake pans with parchment paper. Leave an overhang around sides to lift cookie round out.
In a large bowl, cream the butter and sugar until light and fluffy. Beat in egg and vanilla until combined.
Add flour, baking powder and salt. Mix until just combined. Dough will be stiff. Scrape down bowl as needed.
Pour chocolate chips into batter and gently work in to distribute evenly. Scrape 1/2 of dough into each prepared pan. Spread into even layer, pushing dough out to edges.
Bake for 25 to 30 minutes until starting to crisp at the edges. Cool for 5 minutes on wire rack. Remove from pan to board and cut into wedges while warm.
Chef Tips
Do not over bake. Remove from oven and transfer from pan while baked round is still warm.2 (8-inch) square or round pans can be used. Baking time may increase slightly.