If making spiced nuts, preheat the oven to 350F and line a baking sheet with parchment (use a small baking sheet if you have one). In a microwave safe bowl, add the butter and microwave until just melted. Stir in the sugar, salt, pepper, and cinnamon to combine. Stir in the nuts to coat. Transfer to the baking sheet and spread out into an even layer. Bake for 10-15 minutes, stirring every 5 minutes (mine were perfect after 13 minutes!). Let cool completely.
To make the dressing, add all ingredients into a jar with a lid and shake vigorously until well combined.
On a large serving platter or shallow salad bowl, add the kale (you can also toss it in a large bowl and then transfer to a serving platter if that’s easier!). Drizzle a little bit of the dressing onto the kale and use your hands to massage it into the kale to soften it.
Add the radicchio and ¾ of the remaining dressing and toss to coat. Transfer to your serving platter (if using). Top with apples, cheddar, and nuts. Just before serving, drizzle remaining dressing over top along with some black pepper.