Add the mayonnaise, Dijon mustard, Worcestershire sauce, salt, and pepper to a small bowl. Mix with a small spatula to combine.
Slowly drizzle the olive oil into the bowl, whisking constantly with a small hand whisk, until the ingredients emulsify into a velvety dressing. If the dressing seems too thick (more like a dip) at this point, whisk in a teaspoon of warm water.
Place the chopped Romaine lettuce in a salad bowl. Add the dressing and toss to coat.
Transfer the salad to a serving platter and scatter the Parmesan cheese on top. Serve immediately.
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Notes
I highly recommend using the Worcestershire sauce. However, if you prefer to skip it, you can do so and add a minced garlic clove and a tablespoon of fresh lemon juice instead.
Caesar dressing is meant to be tangy, salty, and savory. These strong flavors are not typically balanced by adding a sweetener. However, if you feel the dressing is too tangy for your taste, you can add a teaspoon of maple syrup.
You can make the dressing 3 days ahead of time and store it in a sealed container in the fridge. Remove it to the counter 20 minutes before using and whisk it again. If it has thickened too much while resting in the fridge, add a teaspoon of warm water and whisk again. The salad cannot be made ahead of time or stored, as the lettuce will wilt.