In a bowl, melt the butter and add the sugar and vanilla extract. Mix well until combined.
Add the egg and the egg yolk, mixing until fully incorporated.
Add the dry ingredients (flour, baking powder, baking soda, and salt) along with the white chocolate chips and chopped chocolate. Mix until a uniform dough forms.
Refrigerate the dough for at least 3 hours.
Preheat the oven to 350°F (180°C).
Line a baking sheet with parchment paper.
Using a #20 scoop, form dough balls and place them on the baking sheet, spacing them apart.
Bake for 15-16 minutes, or until they are just lightly golden.
Use a metal ring to shape the cookies perfectly round if desired.
Let them cool on the baking sheet before handling.
Notes
Measuring Flour: To measure flour correctly, use a spoon to place it into the measuring cup, then level it off with a knife. This prevents adding too much flour, which can make the cookies dry.
Butter substitute: Use coconut oil in the same amount for a slight change in flavor and texture.
Using the Scoop: Using a #20 ice cream scoop will help ensure all the cookies are the same size, which guarantees even baking.
Spacing the Cookies: Leave enough space between each cookie on the baking sheet. This allows them to expand without sticking together.
Oven Monitoring: Every oven can be slightly different, so start checking the cookies at the 15-minute mark to avoid burning them.
Cooling on a Rack: Transferring the cookies to a wire rack to cool completely helps maintain their crispy outside and soft inside texture.
Storage: Store the cookies in an airtight container at room temperature to keep them fresh longer. They can last up to a week.
Freezing: If you want to prepare the cookies ahead of time, you can freeze the dough already shaped into balls. When ready to bake, simply add a couple of minutes to the baking time.
Wheat flour substitute: Use oat flour or gluten-free flour mix in the same amount for a different version.
White sugar substitute: Use coconut sugar or maple syrup for a more natural sweetness.