In a 6-qt. electric pressure cooker, combine the first 4 ingredients. Lock lid; close pressure-release valve. Adjust to pressure-cook on high for 3 minutes. Let pressure release naturally for 5 minutes; quick-release any remaining pressure. Select saute setting; adjust for medium heat. Add the milk, cream cheese and garlic powder. Cook and stir until cream cheese is melted, 3-5 minutes. Stir in spinach, Parmesan cheese, sun-dried tomatoes, basil, salt and pepper. Cook and stir until spinach is wilted. Press cancel. Serve immediately. Garnish with additional basil if desired.