Maple Cake With Maple Syrup Frosting

Ingredients

• 3 cups all purpose flour
• 1 tablespoon baking powder
• 1 teaspoon salt
• 1/2 cup (1 stick) unsalted butter, room temperature
• 2 tablespoons non-hydrogenated solid vegetable shortening, room temperature
• 2 cups pure maple syrup (preferably grade b)
• 3 large egg yolks
• 1 large egg
• 1 1/4 cups whole milk
• 1 cup walnuts, toasted, coarsely chopped
• 3 cups powdered sugar
• 1 8-ounce package cream cheese, room temperature
• 1/2 cup (1 stick) unsalted butter, room temperature
• 2 tablespoons pure maple syrup (preferably grade b)
• toasted walnut halves (for garnish)
• two 8-inch-diameter cake pans with 2-inch-high sides