To make the lemon curd, place the butter, sugar, and lemon juice in a saucepan and heat gently over medium-low heat until the butter has melted and sugar is dissolved. Remove from heat and quickly whisk in the egg yolks.

Place the saucepan back over the heat and stir slowly, but continuously (preferably using a whisk), for 10-15 minutes over very low heat until the curd has thickened. It should be able to coat the back of a wooden spoon well and hold a trail when you swipe your finger through it.

When the lemon curd is ready, pour it into a bowl and cover the surface directly with clingfilm to prevent a skin from forming. Set aside to cool, then transfer to a sterilized jar and store in the fridge for 2 weeks.

Bake some crumble mix in the oven until golden brown and clumpy, pour the curd into a glass or bowl, top with crumble and a dollop of cream and serve.