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.
Halve 1 1⁄2 (10-oz.) containers grape tomatoes. Toss together tomatoes, 1 Tbsp. olive oil, 1⁄2 tsp. kosher salt, and 1⁄2 tsp. black pepper on an aluminum foil-lined baking sheet. Bake at 400°F until browned, about 30 minutes.
Remove grits from heat, and stir in 3⁄4 cup whole buttermilk and 2 Tbsp. unsalted butter. Stir tomatoes, 1⁄4 cup chopped fresh basil, and 2 garlic cloves into grits. Sprinkle servings with crumbled feta cheese.