To make ground oats/oat flour: add ¼ cup of old fashioned/rolled oats to a high powered blender, food processor, spice grinder, etc. Pulse until desired texture. I like mine with a few small chunks of oats. Measure out ¼ cup. Set aside. (you can also chop them up with a knife)
Add 1 Tablespoon softened butter, 1 heaping Tablespoon white sugar, and 1 heaping Tablespoon brown sugar to a medium mixing bowl. Cream together with a hand mixer. It will be pebbly, just press together with a spoon/rubber spatula a few times.
Add ½ Tablespoon milk, ⅛ teaspoon vanilla extract. Mix until incorporated.
Add in ground oats/oat flour (¼ cup). Mix until incorporated. It might be pebbly here too, if so, press together with spoon/rubber spatula. If it holds together, great, if not, add a splash of milk at a time until it does.
Fold in about 2 Tablespoons of chocolate chips (or however many you want). Roll into a ball. Enjoy.
Store any leftovers in an airtight container in the refrigerator for up to 5 days (or until it starts to smell off).