To make this Easy Lemon Pudding Cake gluten-free, replace the all-purpose flour in both the batter and the topping with a high-quality 1:1 gluten-free baking blend. Ensure the blend contains xanthan gum or another binder to maintain the cake’s soft texture. Additionally, lightly dust the baking dish with granulated sugar instead of flour to prevent sticking. The pudding layer will remain silky, and the flavor will be just as bright and lemony.