Prepare the Topping
Mix breadcrumbs, Pecorino Romano, chopped parsley, olive oil, salt, and pepper in a small bowl.
Cook the Spinach
Heat olive oil in a pan over low heat. Add garlic slices and cook until golden. Remove garlic and add red pepper flakes.
Toss spinach in the flavored oil until wilted. Remove from heat.
Cook the Pasta
Boil linguine in salted water. Reserve ½ cup of pasta water before draining.
Combine and Bake
Mix pasta, spinach, and reserved water. Top with breadcrumbs and Pecorino Romano.
Broil for 2 minutes until breadcrumbs are golden.