Prep a baking sheet with parchment paper and set aside.
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
1½ cups all-purpose flour, ½ tsp baking powder, ½ tsp baking soda, ½ tsp salt
In a separate large bowl, use an electric mixer to cream the butter and both sugars together until light and fluffy, about 1-2 minutes. Add the vanilla and egg, mixing until combined.
½ cup unsalted butter , ⅓ cup granulated sugar, ½ cup light brown sugar, 2 tsp vanilla extract, 1 large egg
Add in dry ingredients. Mix until everything is combined, but don’t over-mix. Use a rubber spatula to fold in the chocolate chips/chopped chocolate.
1 cup semi-sweet chocolate
Use a large cookie scoop (about 3 tbsp) to scoop out cookie dough, and use your hands to press the cookie dough into a flat disc. Take a square of the chocolate bar and press it into the middle of the cookie dough. Fold up the sides of the cookie and pinch the dough around the chocolate square, making sure it is fully covered.
extra chocolate squares for filling
Place the cookie dough ball on the parchment paper-lined baking sheet and place in the fridge to chill for at least 30 minutes.
Once the cookies are chilled, pre-heat the oven to 350° F. Line a baking sheet with parchment paper and set aside.
Bake for 10-12 minutes, until the edges are lightly golden brown but the middle is still underdone. Press a few extra chocolate chips into the tops of the cookies as soon as they come out of the oven. Let them sit on the pan for about 5 minutes and then transfer to a wire cooling rack and let them cool completely.