Prepare the Butter: Melt the 1 ½ cups of butter in a microwave-safe bowl in 20-second intervals until fully melted. Let it cool for 15-20 minutes to room temperature. This prevents curdling when mixed with eggs.
Mix Sugars and Butter: In a large mixing bowl or stand mixer, combine the cooled butter with 1 ½ cups brown sugar and 1 cup white sugar. Beat on medium speed for about 4 minutes until light and fluffy. Scrape down the sides as needed.
Add Eggs and Vanilla: Incorporate the egg, egg yolk, and 1 tablespoon vanilla extract one at a time, mixing for 30 seconds after each addition. Dissolve 1 teaspoon baking soda in 2 tablespoons hot water and add it to the mixture, beating until combined.
Combine Dry Ingredients: In a separate bowl, whisk together 2 cups all-purpose flour, 1 cup cake flour, 1 teaspoon baking powder, 1 teaspoon cinnamon, and 1 ½ teaspoons salt.
Incorporate Dry into Wet: Gradually add the dry mixture to the wet ingredients, ½ cup at a time, mixing on low speed until just combined. Avoid overmixing to keep cookies tender.
Add Mix-Ins: Using a spatula or wooden spoon, fold in 1 cup white chocolate chips, 1 cup milk chocolate chips, and 1 cup chopped pecans (if using). The dough will be thick and sticky.
Chill the Dough: Cover the bowl with plastic wrap and refrigerate for at least 3 hours, or ideally overnight. This step is crucial for the signature chewy texture in the Donna Kelce cookie recipe.
Bake the Cookies: Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper. Scoop dough into 1 ½ tablespoon mounds, spacing them 2-3 inches apart. Bake for 10-12 minutes for small cookies or 13-15 minutes for larger ones, until edges are golden but centers are soft.
Cool and Enjoy: Remove from oven and let cookies cool on the sheet for 5-10 minutes before transferring to a wire rack. They firm up as they cool.