Grilled Romaine Lettuce with Blueberries, Avocado and Creamy Lemon Tarragon Vinaigrette

"If you have never grilled romaine lettuce, can we even be friends? If you aren’t adding blueberries to your salads, are you even living? If you’ve never made my Creamy Lemon Tarragon Vinaigrette, but why though?"