Prep: Ensure grill grates are clean; preheat grill to 450℉.
Season: Meanwhile, prepare your veggies and drizzle them with 1-2 tablespoons extra virgin olive oil (or avocado oil). Sprinkle them lightly with 1-2 teaspoons kosher salt and 1 teaspoon ground black pepper.
Place on the Grill: Once grill is hot add your vegetables in a single layer (you might have to do more than one batch depending upon how much you are grilling) over direct heat. Close the grill lid and let cook about 2-3 minutes.
Flip: Open the grill and flip the zucchini, bell peppers and yellow squash. Rotate the asparagus. Close grill and let cook another 1-2 minutes. Then open and flip the onions. Close the grill.
Finish: After another 2-3 minutes open the grill and the zucchini, bell pepper, asparagus and yellow squash should be done (if they don't look done enough just close the lid and let them cook a bit more). Otherwise, place them on a platter. Let the onion cook another 1-2 minutes and then remove them from the grill as well.*
Serve: Enjoy immediately!
Notes
Cook times vary: every grill is different - some can be hotter than others. Always use your best judgment - if you like a more crunchy veggie - don't cook as long. If you like a really well-cooked veggie - cook a minute or two longer. That being said, veggies really don't take too long to cook on the grill so stay close and watch them carefully.
Storage: any grilled vegetable leftovers can be stored in an airtight container in the fridge for 3-4 days.