Maple Walnut Cake

Ingredients

• 1/2 cup unsalted butter, softened
• 1-1/2 cups packed light brown sugar
• 3 large eggs, room temperature
• 1 teaspoon maple flavoring or maple syrup
• 2 cups all-purpose flour
• 1 teaspoon baking powder
• 1 teaspoon baking soda
• 1/4 teaspoon salt
• 1 cup buttermilk
• 1 tablespoon unsalted butter
• 1-1/2 cups coarsely chopped walnuts
• 1 tablespoon maple syrup
• 1/4 teaspoon salt
• 2 cups unsalted butter, softened
• 1 teaspoon maple flavoring or maple syrup
• 1/4 teaspoon salt
• 5 cups confectioners' sugar
• 1/4 to 1/2 cup half-and-half cream
• 3 tablespoons maple syrup, divided