Make Cider-Glazed Apple-Walnut Cake In Your Slow Cooker!

Ingredients

• Butter, for the pan
• 1 1/2 cups all-purpose flour
• 1 cup packed brown sugar
• 1 1/2 teaspoons baking powder
• 1 teaspoon ground cinnamon
• 1/4 teaspoon salt
• 2 large eggs
• 1/4 cup whole milk
• 2 tablespoons canola or vegetable oil
• 1 teaspoon pure vanilla extract
• 1 firm apple (such as Braeburn or Granny Smith)
• 1/3 cup apple cider
• 1 tablespoon unsalted butter
• 1/3 cup confectioners' sugar