Start off by sifting the dry ingredients. Place a fine-mesh sieve over a large mixing bowl. Then add 2 cups all-purpose flour, 1/2 teaspoon baking soda, 1/2 teaspoon baking powder, 1/2 teaspoon salt, and 1/4 teaspoon cornstarch. Sift everything into the bowl and set it aside for later.
In a separate mixing bowl, add 3/4 cup unsalted melted butter, 3/4 cup golden brown sugar, and 3/4 cup granulated sugar. Use a whisk to mix the butter and sugar together for at least 1 minute.
Now add 1 large room temperature egg and 1 egg yolk, along with 1 teaspoon vanilla extract. Mix again using the whisk.
Now add in all the dry ingredients at once and use a spatula to mix everything together.
line a baking sheet with parchment paper then scoop out mounds of the cookie dough using a medium-sized cookie scoop. I like to take the cookie dough ball back into my hand and round it out for a more even-looking cookie. You can also add a few extra chocolate chips and chopped macadamia nuts on top. But that’s optional.
Now bake the cookies at 350 degrees Fahrenheit for 10 minutes.
Make these ahead of time- You can freeze the cookie dough by scooping it into balls, flash freezing them on a tray for an hour or 2, then transferring them to a ziplock freezer bag. Keep frozen for up to 3 months.
Leave space between the cookie dough balls- These cookies spread quite a bit, so leave about 2 inches of space between the dough balls to allow for it.
Allow the cookies to set- They will be very soft when they come out of the oven, so let them set for a few minutes on the baking sheet before transferring them to the cooling rack so they don't break.