Grate rind from lemon; set aside.
Cut lemon in half; squeeze juice into a small bowl.
In a large non-stick skillet, over medium heat, heat 3 tablespoons oil; add onion and garlic.
Cook 8 minutes; stirring frequently.
Add shrimp, seasoning, lemon rind, and lemon juice.
Sauté 4 minutes or just until shrimp turns pink.
Remove from heat and stir in parsley.
Serve shrimp mixture over cauliflower grits.