Make the dressing. Add all of the ingredients to the bowl of your food processor with the blade attachment. Process until smooth. Set aside .Pre-heat your grill to high. Husk corn and brush with olive oil. Add the corn and cook on all sides until some of the kernels begin to blacken, about 5-7 minutes total. Remove the corn from the grill and set aside to cool . Once the corn is cool enough to handle, cut the kernels off the cob and place them in a bowl. Cut the avocado in half. Remove and discard the seed. Scoop the avocado from the peel and dice it. Add the diced avocado, basil, ¼ tsp. salt, ¼ tsp. pepper and 1 tablespoon of the dressing to the bowl with the corn, stirring gently to combine. Set aside. Cut each romaine heart in half. Drizzle the cut side of the romaine lettuce with about 1 tablespoon of olive oil. Sprinkle with a pinch of salt and pepper. Add the romaine to the grill, cut side down, and cook for 1-2 minutes. Flip the romaine and cook for an additional 1-2 minutes. Remove from the grill.To serve, place the grilled romaine on a plate, cut side up, and drizzle with some of the dressing. Top with the corn-avocado mixture. Drizzle with additional dressing, if desired. Serve at once.