Chewy Chocolate Chip Cookies

• 2¼ cups all-purpose flour
• 1 tsp baking soda
• 1½ tsp cornstarch
• ½ tsp salt
• ¾ cup unsalted butter
• ¾ cup brown sugar
• ½ cup granulated sugar
• 1 large egg + egg yolk
• 2 tsp pure vanilla extract
• 1¼ cup semi-sweet chocolate chips

• Whisk the flour, baking soda, cornstarch, and salt together in a large bowl. Set aside.
• In a medium bowl, whisk the melted butter, brown sugar, and granulated sugar together until no brown sugar lumps remain. Whisk in the egg and egg yolk. Finally, whisk in the vanilla extract. The mixture will be thin. Pour into dry ingredients and mix together with a large spoon or rubber spatula. The dough will be very soft, thick, and appear greasy. Fold in the chocolate chips. The chocolate chips may not stick to the dough because of the melted butter, but do your best to combine them.
• Cover the dough tightly and chill in the refrigerator for at least 2 or 3 hours or up to 3 days. I highly recommend chilling the cookie dough overnight for less spreading. Take the dough out of the refrigerator and allow it to slightly soften at room temperature for 10 minutes.
• Preheat oven to 325°F (163°C). Line large baking sheets with parchment paper or silicone baking mats. Set aside.
• Using a cookie scoop or tbsp measuring spoon, measure 3 scant tbsps of dough for XL cookies or 2 heaping tbsps of dough for medium/large cookies. Roll into a ball, making sure the shape is taller rather than wide. This helps the cookies bake up thicker. Repeat with remaining dough. Place 8 to 9 balls of dough onto each cookie sheet.
• Bake the cookies for 12 to 13 minutes or until the edges are very lightly browned. The centers will look very soft, but the cookies will continue to set as they cool. Cool on the baking sheet for 10 minutes. Meanwhile, press a few extra chocolate chips into the tops of the warm cookies. This is optional and only for looks. After 10 minutes of cooling on the baking sheets, transfer cookies to a wire rack to cool completely.

• * * NOTE * *
• You can make the cookie dough and chill it in the refrigerator for up to 2 or 3 days. Allow to come to room temperature then continue with step 5. Baked cookies freeze well for up to 3 months. Unbaked cookie dough balls freeze well for up to 3 months. Bake frozen cookie dough balls for an extra minute, no need to thaw.
• If you do not have cornstarch, you can leave it out. The cookies are still very soft.
• You can add anything including chopped nuts, M&Ms, white chocolate chips, dried cranberries, chopped peanut butter cups, etc. I love them with 3/4 cup (135g) butterscotch morsels and 1/2 cup (100g) Reeses Pieces. You could even add 1/2 cup (80g) sprinkles to make a sprinkle chocolate chip cookie.
• Room temperature egg + egg yolk are best. Typically, if a recipe calls for room temperature or melted butter, it is good practice to use room temperature eggs as well.