To make this Cranberry Butter Cake gluten free, replace the yellow cake mix with a certified gluten-free yellow cake mix. Also confirm that the powdered sugar, vanilla extract, and all packaged ingredients are certified gluten free and free from cross-contamination if needed for strict dietary requirements. Because gluten-free cake mixes can vary slightly in texture, press the base mixture gently and evenly into the pan, and monitor the baking time closely, as the cake may bake a little faster or slower depending on the mix used.