Start by cooking the grits- bring chicken broth to rolling boil in large pot. Whisk in grits, salt and pepper and reduce heat to medium and cook 15 minutes, stirring occasionally.
While the grits are cooking, preheat a large skillet over medium heat. Sauté bacon and onions together until bacon starts to crisp and onions have browned, 5 minutes. Stir in garlic, shrimp, salt and pepper. Stir another 3 minutes until shrimp are bright pink and thoroughly cooked. Remove from heat.
Finish grits by melting in butter and cheeses. Taste and adjust seasonings.
Spoon grits into bowl and top with shrimp mixture. Top with parsley. Serve immediately.