To prepare a gluten-free Pumpkin Custard Recipe, simply replace the all-purpose flour with gluten-free flour blend, cornstarch, or arrowroot powder. Because the recipe uses only a small amount of flour for stabilization, these substitutes work well and do not significantly affect texture or flavor. Always ensure that the pumpkin purée, vanilla extract, and spices used are certified gluten-free if preparing for someone with gluten sensitivity or celiac disease.