Bring the water to a boil in a heavy saucepan then reduce the heat to moderate, so that it simmers gently. Add the grits in a slow stream, whisking constantly to keep lumps from forming. Continue whisking for about 3 minutes after all the grits have been added, then reduce the heat to low and cook, stirring regularly to keep from scorching, until the grits are creamy and fully tender, 30 to 40 minutes. Cover and keep warm over very low heat until ready to serve.
Meanwhile, cook the bacon in a heavy skillet over moderately high heat until crisp, 7 to 8 minutes.
While the bacon cooks, trim the scallions and slice them into 1/2-inch pieces. When the bacon is ready, transfer it to a paper towel-lined plate to cool. Add the scallions and garlic to the bacon fat in the skillet and cook over moderately high heat until crisp-tender, about 5 minutes. Season with 1/2 teaspoon salt and plenty of freshly ground black pepper. Add the cream, reduce the heat, and simmer until slightly thickened, 4 to 5 minutes. Grate a little nutmeg over the scallion mixture.
To serve, spoon the grits into warm bowls and top with plenty of the creamed scallions. Crumble the bacon over each bowl and serve at once.
Excerpted from Onions Etcetera: The Essential Allium Cookbook by Kate Winslow and Guy Ambrosino. Copyright © 2017 by Kate Winslow and Guy Ambrosino. Published by Burgess Lea Press.