Preheat the oven to 400 degrees F and line a baking sheet with parchment paper. Set it aside.
Measure out one cup of dry cereal and place it into a food processor or a sandwich baggie and seal closed. Crush the cereal into a fine crumb. There should be just shy of ¾ cups of cereal crumbs.
In a medium sized mixing bowl combine the flour, cereal crumbs, pudding mix, cornstarch, baking powder, baking soda, and salt with a whisk until combined. Set aside.
In a large mixing bowl, cream together the butter and sugar until light and fluffy (about 2-3 minutes).
Blend in the eggs, egg yolks, and vanilla. Scrape down the sides of the bowl as needed.
Add the flour mixture into the wet mixture in 3 same sized portions, mixing well on low speed between each until combined. Do not overmix.
Note that the dough will become very thick so you may need to mix the remaining flour in by hand.
Stir in the white chocolate chips and the remaining 1 cup of dry cereal (not crushed) until evenly distributed.
Scoop the dough out into ¼ cup sized portions. Roll into a ball and place about 2 inches apart on your baking sheet.
Bake in the oven for 8-10 minutes or until just the edges look set, the tops are no longer glossy and there's just the lightest hint of darkening on the top.
Let the cookies rest on the baking sheet for about 5 minutes to finish cooking and settle. This makes it easier to pick them up and put on a wire rack.