Preheat the broiler and place an oven rack four to six inches from the heating element.

Shuck the corn and remove the silks. Cut the kernels off the cobs and place on a low-sided baking sheet in a single layer (thick strips of corn are okay). Add the onion. Drizzle with one tablespoon oil, sprinkle with salt and pepper, and toss.

Broil three to five minutes, until charred in spots. Set aside to cool partially.

Prepare the dressing: In a jar with a tight-fitting lid, combine vinegar, honey, lemon juice, salt, garlic powder, basil, and oil. Seal and shake well until fully combined.

Assemble: Add corn and onions to a bowl. Add avocados, cherry tomatoes, radishes, and cheese. Right before serving, toss with dressing to taste.