Preheat the oven to 350°F (175°C). Grease and flour a 10-inch Bundt or tube pan.
In a medium bowl, toss diced apples with 1 tablespoon white sugar and 1 teaspoon cinnamon; set aside.
Sift together the flour, baking powder, and salt; set aside.
In a large bowl, combine 2 cups of white sugar, vegetable oil, orange juice, vanilla extract, and eggs. Beat at high speed until smooth.
Gradually mix the dry ingredients into the wet mixture, then fold in the chopped walnuts.
Pour ⅓ of the batter into the prepared pan, sprinkle with half of the apple mixture. Alternate layers, ending with the batter.
Bake for 55-60 minutes, or until a toothpick inserted comes out clean. Let cool for 10 minutes in the pan, then transfer to a wire rack to cool completely.
Dust with confectioners’ sugar before serving.
