Grill the corn for 2-3 minutes, turning occasionally to cook all sides.
Remove and allow to cool enough to handle.
Cut the kernels off the corn and place in a bowl. (You can skip the grilling and cook the corn in the skillet with the other veggies or use frozen, thawed corn.)
Heat the oil in a large skillet over medium heat.
Add the onion to the pan and cook until softened, approximately 2-3 minutes.
Stir in the garlic and cook for an additional minute.
Add the zucchini and bell pepper, continuing to cook for 2–3 minutes, just until crisp-tender.
Stir in the lima beans and corn. Cook for 1–2 minutes, then stir in the tomatoes just until warmed through.
Remove the pan from the heat before sprinkling with green onions, parmesan, and basil.
Serve warm or at room temperature.
Video
Notes
This succotash can be made up to 3 days in advance and can be served warm or at room temperature.
For the freshest flavor, add the basil and parmesan just before serving.
Frozen thawed corn can be used in place of fresh corn; skip the grilling step and add it directly to the skillet.