To make this recipe gluten free, replace the all-purpose flour in both the bread and topping with a high-quality 1:1 gluten-free baking flour blend that contains xanthan gum, or add xanthan gum if your blend does not include it. Also verify that the baking powder, vanilla extract, confectioners’ sugar, and any packaged ingredients are certified gluten free or free from cross-contact concerns. Because gluten-free loaves can be a bit more delicate, allow the bread to cool fully before slicing to help it hold its shape better.