Preheat the oven to 350℉.
Generously spray or grease and flour a standard Bundt cake pan or two 5-cup smaller Bundt pans.
In a small bowl, mix the cinnamon, sugar, and apples together. Set this aside while making the cake batter. It will create a liquid syrup which you will use also.
In a large bowl, by hand or with a mixer, beat the eggs, oil, orange juice, vanilla extract and sugar until smooth.
In another bowl, mix the flour, baking powder, and salt and add it to the egg mixture.
Pour half of the cake batter into the pan.
Top with half the apples.
Spread the rest of the cake batter on top.
Spread the remaining apples and drizzle the liquid syrup from the apples all over the top too.
Bake at 350℉ for 70-80 minutes or until a cake tester comes out clean.
Cool the cake in the pan on a wire rack for 15 minutes. With a knife, loosen the edges of the cake and invert it onto a serving plate.
Store at room temperature for 3 days or in the refrigerator for a week.