The Perfect Chocolate Chip Cookie (or at least my version)

Ah, the perfect chocolate chip cookie.  I know, I know: "It doesn't exist" or you think you've already found it. One friend even went so far as to call the perfect CCC a "unicorn". Now, I haven't made every chocolate chip cookie recipe there is, but I've tried my fair share and none of them seemed to yield what I would deem the perfect cookie. For me some came out too flat or too floury. Other just didn't puff up enough or weren't quite chewy enough. I wanted a cookie that was soft, but still chewy, not too thick but not crispy either, and filled with buttery deliciousness and plenty of chocolaty goodness. I tried dozens of recipes, tweaked some of them here and there, but I still was coming out with cookies that weren't up to my standard. While the mister and Little Ladies number 1 and number 2 didn't have any complaints, I was getting frustrated with my lack of results. Finally, I did a LOT of research. I read recipes, I read blogs, I read cookbooks. Finally, after over a year of experimentation I came up with a recipe that lived up to my standard. It puffed up in the oven but didn't fall flat, it had a buttery taste without being too greasy, and it was soft and chewy at the same time. So, without further ado I give you.....

THE PERFECT CHOCOLATE CHIP COOKIE

Yields 30 cookies

Ingredients:
1/2 cup of butter (1 stick) softened
1/2 cup shortening
3/4 cup packed light brown sugar
3/4 cup white sugar
1 whole egg + 1 yolk
1 tsp real vanilla extract (spend the few extra dollars! It's totally worth it)
2 1/2 cups of flour (I use a mix, 1 1/2 cups of white all purpose flour, 1 cup whole wheat flour)**
1 tsp salt
1 tsp baking soda
1-2 cups of semisweet chocolate chips (I prefer less chocolate in my cookies personally, so I used 1 cup. I also used a mix of chocolate chips: 1/2 semi sweet chips, and 1/2 semi sweet mini chips)

Instructions:
Pre-heat oven to 375 degrees Fahrenheit
In a medium bowl cream together butter, shortening and sugars until well combined
Add in egg and egg yolk until fully combined
Stir in vanilla and mix until fully combined
In a separate bowl sift together flour, salt and baking soda
Gradually add dry ingredients to wet ingredients until well combined
Drop by rounded table spoons (I use a cookie scoop) onto ungreased cookie sheet
Bake cookies for 9-13 minutes (12 was the perfect amount for my oven)
Cool for 2 minutes on cookie sheet, then transfer to a clean towel or cooling rack and allow to cool completely

** I live in Utah where we are well above sea level. If you live at or near sea level you may find that you have better results decreasing your flour to 2 1/4 cups.