Preheat oven to 350F. In a bowl, whisk together: olive oil, maple syrup, cayenne pepper. Stir in 1 Tbs of rosemary and 2 teaspoon of thyme. Add walnut halves. Toss well to coat. Spread evenly on a baking sheet. Bake until fragrant and crisp, 10-12 min. As soon as it comes out of the oven, sprinkle with the remaining 1 teaspoon thyme and salt. Cool completely.