First, make the curd. Put the rhubarb, a pinch of sugar and the orange juice in a pan over a medium heat and cover with a lid. Cook for 10-15 mins until the rhubarb is very tender. Remove from the heat.
Pass the rhubarb through a fine sieve, pushing it to squeeze out as much pulp as possible. Keep the flesh in the sieve to incorporate later.
Whisk the eggs, egg yolks and sugar together until pale and frothy. Melt the butter steadily in a pan on a low heat. Once melted, slowly pour in the egg mix and orange zest, stirring continuously. Add in the strained rhubarb pulp and mix to combine, continuing to cook gently until the curd has thickened like custard. This could take 10-12 mins, but be patient and do not turn up the heat, as you might scramble the eggs.
Once the curd has thickened, transfer it to a bowl and whisk until smooth. At this point I like to add back in the rhubarb flesh from the sieve, to give more body to the dessert – but if you want a smooth curd, don’t do this.
Whip the cream, stopping just before soft peaks start to form. Fold in the yogurt, 300g of the curd and most of the amaretti biscuits.
Spoon the mix into eight glasses and sprinkle on the reserved amaretti. Save the remaining curd to use on pancakes, granola or to make little tartlets. Store it in a sterilised jar (wash a jar in hot soapy water, rinse, then put in the oven upside down at 120C/100C fan/gas 1 /2 for 15 mins to dry).