In a medium saucepan, bring 4 cups of water or chicken broth to a boil. Add a pinch of salt. Gradually whisk in the grits, reducing the heat to low. Stir occasionally and cook for 20-25 minutes until thickened and creamy.
Once the grits are cooked, stir in the butter, cheddar cheese, salt, and pepper. Keep warm while you prepare the shrimp.
In a large skillet over medium heat, melt 2 tablespoons of butter. Add the minced garlic and cook for about 1 minute until fragrant.
Add the shrimp to the skillet and season with salt, pepper, and red pepper flakes. Cook for about 2-3 minutes on each side until the shrimp are pink and opaque.
Stir in the lemon zest and juice, cooking for an additional minute to combine the flavors. Remove from heat and stir in the chopped parsley.
To serve, spoon a generous portion of the creamy grits onto plates, and top them with the lemon garlic shrimp. Garnish with lemon wedges and additional parsley, if desired.