Preheat the flat top griddle on medium-high heat (400ºF to 425ºF). Use an infrared temperature gun to check the temperature. Prepare the vegetables while the grill is preheating.
Slice the vegetables into bite-sized pieces, about 1 inch. Add to a large bowl and toss veggies with melted butter and season with all-purpose seasoning.
Season the grill with enough olive oil to prevent sticking. Add the vegetables to the griddle. To get that smoky flavor, do not move the vegetables for 2-3 minutes before flipping. This will allow a little charring to occur and provide more flavor. Flip the vegetables with a long metal spatula. Cook on the other side for an additional 2-3 minutes.
If the vegetables look nicely sauteed, then test the zucchini and asparagus by piercing them with a fork. If the fork slides in easily then the zucchini and asparagus are ready. Taste to check for seasoning, and add more if needed before serving.
Notes
What other vegetables are good to cook on a Blackstone Griddle? Most vegetables will work in this recipe. If using root vegetables like carrots, potatoes, or sweet potatoes, add them first and cook on the grill for 5 minutes before adding softer vegetables like onions, broccoli, zucchini, and bell pepper. To get that smoky flavor, do not move the vegetables for 2-3 minutes before flipping. This will allow a little charring to occur and provide even more flavor.How to Store Veggies:Leftover veggies will keep well for up to 4 or 5 days in the refrigerator.