Heat skillet on medium heat and add olive oil, allow to get hot.
Add onions and let cook. While they are sauteing cut squash and zucchini into rounds and corn off the cob.
Once the onion is well on it's way to caramelizing, add Splenda and stir well.
Add the rest of the veggies and let cook stirring every so often.
Add the onion soup mix and stir.
When the squash and zucchini are tender (limp) it's ready.