In a skillet over medium heat, cook the bacon until crisp, 10 to 12 minutes. Remove it to a paper towel-lined plate.
Meanwhile, bring 4 cups of water to a boil in a medium saucepan. Whisk in the grits and salt. Reduce the heat to low, cover and cook, stirring occasionally, for 30 minutes.
Stir in the half-and-half and cook until the grits are tender and creamy, about 20 more minutes.
Add the pimientos, cream cheese, Cheddar and mustard and stir until melted together and combined. Chop the bacon into small pieces and add to the grits. Stir in the pepper and serve.
If making ahead, allow the dish to cool, then cover and refrigerate. Reheat, covered in foil, at 350 degrees F for 30 minutes or until heated through.
When accompanying Spicy Stewed Beef, pour into a 9-by-13-inch baking dish, spoon the beef over the top and serve immediately.