Preheat oven to 425 degrees F. Lightly oil a rimmed 13x9-inch baking sheet with olive oil.

Use vegetable peeler to peel squash into long thin ribbons into a large bowl. Toss squash with 2 Tbsp. olive oil and a pinch of both sea salt and pepper.

Transfer squash ribbons in a single layer on the prepared baking sheet. Bake for 15 minutes or until tender then turn on your broiler and broil for 1 minute until the ribbons are lightly browned.

Remove from the oven and transfer to a large bowl with radicchio, kale and mushrooms.

In a small bowl, whisk vinegar, remaining 2 Tbsp. olive oil, Dijon mustard, honey, shallots, sea salt and pepper. Season to taste for this dressing because some apple cider vinegars and Dijon's can be overpowering so use a small amount at first then drizzle over kale mixture and serve.