Preheat the oven to 375°F.
Place the all-purpose flour, cornstarch, baking powder, and salt in a medium size bowl. Then, using a fork or a small whisk, stir the dry ingredients together. Set bowl aside until ready to use.
Cube cold unsalted butter and place it in the bowl of an electric stand mixer. Then add light brown sugar and white sugar. Attach the paddle and turn the machine on low for about a minute. Then increase the speed to medium, and let it mix for about five minutes, until a dough forms.
Turn the mixer off, lower the bowl, and scrape down the inside and paddle. Raise the bowl, turn the machine on low, and add the eggs and vanilla extract. Increase the speed to medium and let mix for about three minutes.
Turn the machine off, lower the bowl, and scrape the inside and paddle. Raise the bowl and turn the machine on low, and add the flour, about a cup at a time, then mix for about a minute after the last addition, until well combined.
Turn the machine off, lower the bowl, and scrape the inside and paddle. Raise the bowl and turn the machine on low, and add the semi-sweet mini chocolate chips.
Remove 66 semi-sweet chocolate chunks, and set aside for topping the cookie num nums. Add the remaining chunks to cookie dough and mix until incorporated.
Line a half-sheet pan with parchment paper and put on a pair of vinyl gloves. Then, using a ½ cup ice cream scoop, portion the dough into 11 balls and place them on the parchment paper. (If you want to weigh the dough balls, they should weigh about 4 ½ ounces each.)
Line a half-sheet pan with a silpat baking mat and place 11-3.5 inch Crumbcake papers on top. Roll the dough balls slightly in your gloved hands and place into the baking paper. Press the dough out so it fills the bottom of the paper cup. Then, press six semi-sweet chocolate chunks into the top of each cookie dough.
Place in the 375°F oven, then reduce the oven temperature to 350°F, and bake for 23-25 minutes.
Remove the pan from the oven and let it cool on a wire rack for about 5 minutes.
After 5 minutes, remove the Cookie Num Nums from the baking sheet and place them on the wire rack to cool.
Yield 11 Cookie Num Nums