Melt 1 1/2 cups butter in the microwave in 20-second increments (do not overdo!). Pour into a mixing bowl or stand mixer. Let cool for 15 to 20 minutes.
Add 1 1/2 cups brown sugar and 1 cup white sugar to the butter mixture and mix for 4 minutes. Scrape down the sides of the bowl.
Add the 1 egg and mix. Then add the egg yolk and mix again.
Add 1 tbsp vanilla and mix for 30 seconds.
Add 1 tsp dissolved baking soda.
In a separate bowl, add 2 cups all purpose flour, 1 cup cake or pastry flour, 1 tsp baking powder, 1 tsp cinnamon and 1 1/2 tsp salt, and mix to combine. Slowly add this mixture 1/2 cup at a time to the mixer, scraping down sides.
Add all 1 cup chocolate chips, and 1 cup white chocolate chips, and 1 cup pecans, if desired, with a wooden spoon.
Put in the refrigerator for at least 3 hours; ideally overnight.
Preheat the oven to 350°.
Before baking, make sure the dough is at room temperature. Scoop dough onto baking sheet, leaving 2 inches between scoops, 5 minutes before baking.
For small cookies, bake for 10 minutes, or until lightly golden around the edges. For larger cookies, bake for 13 to 15 minutes. If you touch the top of the cookie and it bounces back instead of indenting, that means it’s ready. Every oven is different.