Creamy Chicken Pesto Pasta

Name: Creamy Chicken Pesto Pasta
Ingredients: 2 cloves garlic; 1 ounce Parmesan cheese (about 1/2 firmly packed cup finely grated or 1/3 cup store-bought grated), plus more for serving; 1 pound boneless, skinless chicken breasts (about 2 small); 3/4 teaspoon kosher salt, divided, plus more as needed; 1/4 teaspoon freshly ground black pepper; 12 ounces dried penne or other tube shaped pasta; 1 tablespoon olive oil; 5 ounces baby spinach (about 5 cups); 1 cup heavy cream; 1/2 cup basil pesto; Fresh basil leaves, for garnish (optional)