For a rhubarb-lemon version of this recipe, you can replace the vanilla in the cake batter with 2 tbsp (30 ml) of lemon juice and the grated zest of 1 lemon.
The pudding cake can be made in one 10-cup (2.5 liter) soufflé dish. In this case, the baking time is closer to 1 hour 30 minutes.