Maple Walnut Cake

Name: Maple Walnut Cake
Ingredients: 4 tablespoons unsalted butter, melted; 1 cup whole-wheat pastry flour; 1/4 cup canola oil; 3/4 teaspoon baking soda; 3/4 cup gently packed confectioners' sugar; 1/4 teaspoon salt; 1 teaspoon cider vinegar; 2 tablespoons pure maple syrup; 1-2 teaspoons water, if needed; 3/4 cup all-purpose flour; 1/2 cup boiling water; 1 cup chopped pitted dates, (6 ounces); Cake; 2 teaspoons cider vinegar; 1 cup chopped toasted walnuts, (see Tip), divided; 1 large egg; 3/4 cup pure maple syrup, preferably dark amber (Grade B); 1 tablespoon vanilla extract Glaze