Preheat the oven to 350 degrees Fahrenheit.
Add butter to a medium sized bowl with your brown sugar and white sugar, and beat at medium speed for about 2 minutes until nice and creamy.
Add in the egg and vanilla extract and stir till combined.
Add in the flour, cornstarch, baking soda, and salt. Stir till you have a nice and soft dough.
Fold in 3/4 cup of the mini chocolate chips.
Scoop the dough into about 1 teaspoon sized balls (slightly smaller is okay, but don't go much bigger)
Roll the dough into a ball and press 4 of 5 mini chocolate chips onto the top (for looks)
Line the cookie balls onto a cookie sheet lined with a silicone liner or parchment paper, about 1 inch apart.
Bake for 6-7 minutes until the tops are just set. The cookies may look slightly under baked, they'll keep baking on the pan as they cool.
Allow to cool on the pan for 10 minutes, then transfer to a cooling rack to cool completely.