Using a mortar pestle, mash the anchovies and garlic. Once done, add chili flakes, black pepper, lemon juice and extra virgin olive oil. Give it a mix and the dressing is ready.
Arrange the romaine lettuce and sliced red onion in your salad-serving bowl.
Peel the avocado, remove the pit and cut it into chunky slices. Layer the avocadoes on top of the lettuce.
Drizzle the salad dressing and shave Parmesan on top.