Using a large non-stick skillet, heat the olive oil over medium-high heat. Add the onions and garlic and sauté until the onions begin to soften, for about 3 to 4 minutes. Add in the kale, butternut squash, and mushrooms and cook for about 5 to 7 minutes, or until tender. Season with salt and pepper to taste.
Using a small bowl, mash the avocados with a fork, add in the lime juice and season with salt. Mix together, taste and adjust the lime and salt as needed.
To assemble: Spread some light butter onto the toasted waffles and top one with the avocado mixture. Spread evenly over the waffle. Top with the kale and mushroom mixture and top with a fried egg. (If desired, you can top with another waffle and make a sandwich!) Season with more salt and pepper if you'd like and enjoy immediately.