Kim-Joy’s lemon meringue pie bubble bath

Method

1. Heat the oven to 200°C/180°C fan/gas 6. First make the biscuit base. Use a food processor to whizz the cookies to the consistency of fine breadcrumbs or put the cookies inside a sealed plastic bag and crush them with a rolling pin. With this quantity, it’s easiest to do this in smaller batches. Add the crumbs to a mixing bowl along with the melted butter. Mix until all the crumbs are evenly coated and the mixture resembles fine sand.
2. Tip the mixture into the tart tin. Use a drinking glass (or any cup with a flat base and straight sides) to firmly pack in the crumbs, ensuring you cover the base and sides in a roughly even layer. Put on a baking tray and bake for 10 minutes, then set aside while you make the filling. After baking, reduce the oven temperature to 180°C/160°C fan/gas 4.
3. Meanwhile, make the lemon filling. Add the egg yolks to a large mixing bowl and pour in the condensed milk. Whisk until smooth and combined. Add the lemon juice and zest and salt, then whisk again until just combined. The mixture will thicken slightly as the lemon juice reacts with the condensed milk.
4. Pour the mixture over the baked base, then bake for 20–25 minutes. If you gently tap the top using your finger or a spoon, it should feel firm rather than liquid-y but still with a wobble. Put the tin on any heatproof surface, leaving the pie in the tin while it cools to room temperature, then cover and put in the fridge for at least 3 hours.
5. Just before serving, make the meringue topping. Add the egg whites and sugar to a large, heatproof bowl. Set the bowl over a pan filled with barely simmering water, ensuring the bowl does not touch the water. You want around 3cm water in the base of the pan. Whisk until all the sugar has dissolved (the meringue should be hot to the touch and will feel smooth and not gritty between your fingers) or the mixture reaches 70°C. Then add the cream of tartar and whisk on high speed until it is glossy and reaches stiff peaks.
6. You can decorate with toy ducks (skip to the next step, if so) or meringue ducks. To pipe the ducks, spoon a generous heaped tablespoon of meringue into a small piping bag and cut a medium opening. Put a teaspoon of meringue in a second bowl, add orange food dye and stir to combine. Transfer to a small piping bag and cut a small opening. Put a large dessertspoonful of meringue in a third bowl, add the yellow food dye and stir to a combine. Transfer to a small piping bag and cut a large opening. You should now have 3 piping bags: one plain, one yellow (the largest one), and one orange (the smallest one).
7. Push the base of the tart tin upwards, allowing the sides of the tin to come away. Slide a cake lifter (or similar wide spatula) underneath the tart to separate it from the base, then slide onto a serving plate. Spoon the remaining, plain meringue (or all of the meringue, if not piping the ducks) over the lemon filling. Spread it all the way to the edges of the crust, then pile it higher in the centre. Using the back of the spoon, create swirls and peaks in the meringue. You can also use a blow torch to add a little bit of colour, although this is entirely optional as the meringue is already baked.
8. To decorate, finish with toy ducks, or use the piping bags to pipe your ducks onto the pie. Use the yellow meringue for the main duck body: squeeze, then gradually reduce pressure on the bag while pulling the bag away to create the larger head and tapered tail. Use the orange meringue to pipe a little beak on to each duck. Then use the white piping bag to pipe bubbles all around. Dampen the tip of your finger with a little water, then gently tap down any unwanted peaks. For the eyes, use poppy seeds or similar, or pipe them. To pipe the eyes, take a small amount of the remaining meringue and mix with black food dye. Transfer to a piping bag and cut a very small opening, then pipe on small dots. You barely need to squeeze the piping bag (if at all) – just a tiny dab is all you need.