To prepare the grits, combine the chicken stock, milk and garlic powder in a medium pot over medium-high heat. Bring the liquids to a boil and then stir in the grits. Reduce the heat to medium low and cook, stirring frequently, until the grits are tender and have absorbed the liquid, 6 to 8 minutes. Stir in the cheese and season the grits with salt and pepper. Reserve warm.
While the grits are cooking, place a large skillet over medium heat with the butter. Add the onion, bell pepper and garlic to the pan and cook, stirring occasionally, until tender, 3 to 4 minutes. Add the shrimp, tomatoes and juice of the lemon to the pan and simmer until the shrimp are cooked through, 3 to 4 minutes. Stir in the zest of the lemon and tarragon and season the shrimp with salt and pepper.
To serve, spoon the shrimp and pan sauce over the grits.
Recipe courtesy of Patrick Decker