Lightly butter the bottom and sides of a 10-inch skillet or four 4-inch ramekins. Set aside.

In a medium saucepan over medium-high heat, combine the whole milk and water. Cover and bring the mixture to a boil, about 5 minutes.

Reduce the heat to medium. Slowly add the stone-ground grits, kosher salt, and black pepper, stirring constantly to prevent lumps from forming.

Continue stirring until the grits reach the consistency of a thick soup, about 8 minutes.

Reduce the heat to low and simmer the grits for 10 to 15 minutes, stirring every 2 minutes to prevent sticking.

Continue cooking for an additional 10 to 15 minutes, stirring constantly, until the grits are very thick and fully softened.

Remove the saucepan from the heat. Stir in 3/4 c extra sharp cheddar cheese, 3/4 c Monterey Jack cheese, and the unsalted butter. Mix until the cheeses and butter are fully melted and incorporated.

Pour the grits into the prepared skillet or divide them evenly among the ramekins.

Sprinkle the remaining cheddar cheese and Monterey Jack cheese over the top.

Set the oven to broil. Place the skillet or ramekins directly under the heating element for 2 to 3 minutes, or until the cheese topping is melted and lightly browned.

Remove from the oven and serve immediately while hot.