First, prep the roasted red pepper sauce. Drain jar of roasted red peppers. In a food processor add roasted red peppers, 1 tbsp olive oil, basil, garlic, and salt and pepper. Blend until smooth. You can prep ahead of time and even freeze this.
Then, cut all veggies to cook evenly. Slice zucchini on an angle 1/2 inch thick. Slice eggplant lengthwise about 1/2 thick. Cut whole round onion a little less than 1/2 inch, and chop bell pepper into quarters or about 2 inches in diameter. Trim root ends of asparagus.
Once the veggies are prepped toss them in 1 tbsp olive oil, sea salt, and ground black pepper. Add veggies to the grill. Be sure they do not overlap one another.
Grill covered or uncovered for 25 minutes, flipping once halfway. When tender, remove from grill.
Spoon over roasted red pepper sauce to serve.