Preheat the oven to 350°F (175°C) and grease a 12-cup Bundt pan with non-stick spray or butter and a dusting of gluten-free flour.
In a medium mixing bowl, whisk together the gluten-free flour blend, salt, baking powder, baking soda, and ground cinnamon until uniform.
In a separate large mixing bowl, beat the granulated sugar, vegetable oil, eggs, and vanilla extract together using an electric mixer until the mixture is smooth and fully emulsified.
Slowly add the dry ingredient mixture into the wet ingredients, mixing on low speed until just combined.
Gently fold the chopped apples into the batter using a rubber spatula until they are evenly distributed throughout the thick batter.
Transfer the batter into the prepared Bundt pan and smooth the top with a spatula.
Bake for 55 to 60 minutes, or until a wooden skewer or toothpick inserted into the thickest part of the cake comes out clean.
Allow the cake to cool in the pan for 15 minutes to let the structure set before inverting it onto a wire cooling rack to cool completely.