2teaspoonsflaky sea salt or kosher salt, plus more to taste
Preheat an oven to 350°F. In a large bowl, toss mixed nuts with melted butter and maple syrup. Add 2 tablespoons chopped rosemary, dark brown sugar, cayenne pepper and 2 teaspoons flaky sea salt, mixing until the nuts are well coated with the flavorings. Spread nuts out onto a rimmed baking sheet lined with parchment paper. Bake until glazed and golden (about 18 - 20 minutes), stirring twice during the cooking process.*
As soon as the nuts come out of the oven, season with an additional 1 teaspoon chopped fresh rosemary, and flaky sea salt to taste (I added an additional 3/4 teaspoon). Serve warm immediately or store in an airtight container at room temperature for up to 5 days.
* If your oven runs hot, be sure to check the nuts a bit early. Nuts can go from wonderfully golden to bitter and acrid if overcooked.