Bring the grits, 2 cups of the whole milk, butter, and a large pinch of kosher salt to a boil, stirring occasionally so the grits do not burn.
Once the mixture comes to a boil, turn down the heat to medium-low and stir occasionally but vigorously for 20 to 30 seconds at a time. Continue to do this until thick like wet sand. It should take around 15 to 18 minutes or so.
Add ½ cup more milk, stirring occasionally but vigorously for 10 more minutes until thick and creamy.
Serve and enjoy. Grits will thicken even more as they cool.