Preheat the oven to 350F then pull 7 3-inch tart pans and set them aside.
In the mirowave or in a small saucepan, melt the butter then set aside to cool.
In a food processor, grind the 15 graham cracker sheets until the mixture ressmebles flour. Pour that mixture in a large bowl, then grind the 2 graham cracker sheets and set that aside.
Add in the brown sugar, granulated sugar, flour, corn starch, baking soda, and baking powder to the graham cracker mixture in the large bowl. Whisk to combine.
Add in the beaten egg and egg yolk, and the melted and cooled down butter, and stir to form a dough. It will be slightly crumbly.
Using a large cookie scooper, scoop out 7 equally sized cookie dough balls, roll them in the graham cracker mixture you set aside, then press the cookies into the 3 inch tart pan.
Bake the cookies in the tart pans for 8-9 minutes, then let them cool for 5 minutes before flipping them and cooling them on a cooling rack.