Measure out the milk in a jug or measuring container.
Pour the milk into a pan, leaving behind a few tablespoons of milk in the jug.
Heat up the milk in the pan.
Add the custard powder to the remaining milk in the jug and mix well, ensuring it has dissolved completely.
Once the milk in the pan is steaming, add approximately half of the hot milk to the bowl with the dissolved custard powder, mix well and transfer the custard powder mixture to the pan.
Mix well and keep stirring on a low heat for around 5 minutes, until thickened.
Add the lemon juice and maple syrup, and mix well.
Taste and add extra lemon juice or maple syrup, if desired.
Transfer the sauce into a baking dish - I used one measuring 26 cm (10 inch) by 18 cm (7 inch) and 7 cm (2 ½ inch) tall.
For the topping:
Preheat oven to 180 degrees Celsius (350 degrees Fahrenheit).
Place all the ingredients for the topping in a bowl and mix well (no need to sift in the flour) - add the milk a little bit at a time until you get a fairly soft dough (you can also add a tiny splash more milk if it's looking too dry.
Use two tablespoons to place a heaped tablespoon of the dough on top of the lemon sauce.
Repeat for the rest of the mixture - you should be able to make around 12 soft balls.
Bake in the oven for 20-25 minutes until browned and an inserted skewer into the topping comes out clean.
Best enjoyed immediately!
Notes
*You can use any type of plant-based milk, though results do vary depending on which you choose: cashew, oat or coconut milk make a super thick and creamy sauce, whilst almond milk will be less creamy. I like to use rice milk as it creates a lemon curd-like consistency which I love.**If you can’t get hold of a shop-bought custard powder, you can replace it with the same amount cornflour (cornstarch) or arrowroot, which will result in the same texture, though the colour will be considerably less yellow. To add yellow colour, I would suggest adding a tiny pinch of saffron, which I much prefer to turmeric as it has a much milder flavour.***You can alternatively use almond flour.