Toasting the walnuts enhances their flavor and adds a delightful crunch to the salad. Spread the chopped walnuts on a baking sheet and bake in a preheated oven at 350°F (175°C) for 5-7 minutes, or until lightly golden and fragrant. Let cool before adding to the salad. For a vegan option, substitute the feta cheese with a plant-based alternative or simply omit it. Feel free to customize this salad with other ingredients you enjoy. Some great additions include dried cranberries, sunflower seeds, chopped apple, or roasted sweet potatoes. The salad can be prepared ahead of time and stored in the refrigerator for up to 3 days. However, it is best to add the dressing just before serving to prevent the kale from becoming soggy.