How to Make It
Bring 4 cups water, 1 cup whole milk, and 1 1/4 tsp. kosher salt to a boil in a medium saucepan over medium-high. Gradually whisk in 1 cup uncooked stone-ground grits; return to a boil. Reduce heat to medium-low, and simmer, stirring occasionally, until creamy and thickened, 25 to 30 minutes.
Remove from heat, and stir in 3/4 cup whole buttermilk and 2 Tbsp. unsalted butter. Cover and keep warm until ready to serve.