COOK IT.
Boil potatoes on your side burner in heavily salted water for 10 minutes. You want your potatoes to still be firm, but for you to still be able to crush them with a spoon.
Spritz avocado or any high temp cooking oil onto your grill pan. Grill all vegetables on a grill topper to make rotating and moving vegetables around easier to avoid burning.
Repeat this process with your par cooked potatoes. If you omit the boiling step this will still work, just the grilling process will take longer.
Remove all vegetables from grill, cool and then set up your cutting board.
Remove corn from the cobb, remove skin from the peppers and onion and dice.
Slice celery into 1/2 “ pieces
Mix dressing
Add dressing + vegetables to potatoes in a large bowl.
Adjust seasoning