Preheat oven to 375°. Bring 1 tsp. salt and 6 cups water to a boil in a large saucepan over medium-high heat. Gradually whisk in grits, and return to a boil. Reduce heat to medium-low, and cook, whisking often, 15 minutes or until thickened.
Remove grits from heat, and whisk in butter. Whisk about one-fourth of hot grits mixture into eggs; whisk egg mixture into remaining hot grits mixture. Gradually whisk in milk. Whisk in cornmeal and remaining 1/2 tsp. salt. Pour grits mixture into a lightly greased 2 1/2-qt. baking dish.
Bake at 375° for 1 hour to 1 hour and 10 minutes or until golden brown and set.
Cheese Awendaw: Prepare recipe as directed, stirring in 2 cups (8 oz.) shredded smoked Gouda cheese and 1/2 tsp. ground red pepper after cornmeal.
Garlic-and-Herb Awendaw: Prepare recipe as directed, stirring in 1 cup freshly grated Parmesan cheese; 1/4 cup each finely chopped fresh flat-leaf parsley, basil, and chives; 2 Tbsp. chopped fresh tarragon; 3 garlic cloves, pressed; and 1 tsp. freshly ground black pepper after cornmeal.
Fresh Corn Awendaw: Cut kernels from fresh ears of corn to equal 2 cups, and place in a bowl. Using the dull side of a knife blade, scrape milk and remaining pulp from cobs into bowl. Prepare recipe as directed, increasing salt to 1 tsp. in Step 2 and stirring in corn kernels after cornmeal.