Make the buttermilk ranch dressing by combining the buttermilk, mayonnaise, sour cream, minced garlic, lemon juice, dill, parsley, and onion powder; whisk until well combined. Taste then season with sea salt and freshly cracked pepper, to taste. Place in the refrigerator to allow flavors to mingle until you are ready to use.
Grill the corn by heating a dry grill pan over medium heat. Add the shucked corn to the hot grill pan and cook, turning occasionally, until golden brown. In my grill pan, it took about 15 minutes. Let the corn cool then cut the kernels off the cob with a knife. Set aside.
Prepare the salad by placing the chopped romaine in a serving bowl. Add the cooled corn on top along with the avocado slices, tomato wedges, and red onion slices. Top with lots of freshly cracked pepper.
Serve immediately with the buttermilk ranch dressing on the side. Enjoy.