Asparagus Pasta with Lemon and Parmesan

Name: Asparagus Pasta with Lemon and Parmesan
Ingredients: 1 pound asparagus, preferably thin; 4 cloves garlic; 1 medium lemon; 1 ounce Parmesan cheese (1/2 cup firmly packed freshly grated or 1/3 cup store-bought grated), plus more for serving; 1 pound dried spaghetti or other long pasta, such as linguine or bucatini; 4 tablespoons olive oil, divided; 1 1/2 teaspoons kosher salt, divided; 1/4 teaspoon freshly ground black pepper; 1/4 teaspoon red pepper flakes (optional); Fresh basil leaves, for serving (optional)