21st March 2019
Rhubarb & Custard Sandwich Biscuits
As part of my new monthly baking challenge, I set myself the challenge of baking with rhubarb during March- an ingredient I’ve never really baked with before. I’ve already made a rhubarb and almond tart, but I wanted to try something that incorporated the classic flavours of rhubarb and custard.
I spotted this recipe in one of my Bake-Off cookbooks and thought I would give them a go – home-made rhubarb curd sandwiched between a buttery custard biscuit? Heavenly.
And I have to say, while biscuits aren’t really my favourite things to bake, these are some of the nicest biscuits I have ever made. If you love the classic flavour combination of rhubarb and custard, you’ll have a wonderfully nostalgic trip down memory lane with these beauties.
When I first saw the recipe for this and all the different steps, I thought it sounded like a bit of a faff. Turns out, it was actually fairly straightforward, you just need to make a little bit of extra effort to make the rhubarb curd (it is worth it though!). If you really don’t want to make rhubarb curd, I’m sure you could swap for store-bought rhubarb jam.
Ingredients for the curd
- 400g rhubarb, chopped into thumb size pieces
- 1 large egg
- 55g caster sugar
- 1 1/2 tsp cornflour
- Pink food colouring (optional)
Ingredients for the biscuits
- 40g icing sugar
- 185g plain flour
- 40g custard powder
- 185g softened butter
- 1/2tsp vanilla bean paste
Ingredients for the buttercream
- 75g softened butter
- 150g icing sugar
Method for the curd:
- Begin by making the rhubarb curd. Put the rhubarb into a food processor or blender and blitz until you are left with rhubarb mush. Tip the rhubarb into a fine-mesh sieve suspended over a clean bowl and press and squeeze the rhubarb until all the juice is released. You will need 100ml. Discard the rhubarb mush.
- Whisk the egg and sugar together until combined. In a separate bowl, mix a tiny splash of rhubarb juice with the cornflour to make a smooth paste – add this to the egg mixture along with the rest of the rhubarb juice
- Place into a medium saucepan and bring to a simmer while continuously whisking. Add the butter to the mixture and whisk on medium heat until it has thickened. Pour into a clean bowl (you made need to pour into through a fine mesh sieve to get rid of any lumps!), place some clingfilm over the surface of the curd to prevent a skin from forming and leave to cool down completely.
- OPTIONAL: I added a dash of pink food colouring to the curd to make it more vibrant – but this isn’t necessary if you don’t have any – they will still taste and look amazing without!
Method for the biscuits:
- Next, make the biscuits. Preheat the oven to 18ooc and grease and line 2 large baking trays
- Place all the dry ingredients into a food processor along with the softened butter and vanilla and then pulse until it forms a sticky dough. Using your hands, take spoonfuls of the dough and roll them into balls – place them onto a baking tray (I was able to get about 16 balls of dough) and then using a fork, press the dough to flatten them slightly
- Put the trays in the fridge to chill for 15 minutes and then bake in the oven for around 15 minutes or until the biscuits are a light golden colour. Leave to cool.
Method for the buttercream:
- Place the butter into a large bowl and whisk for a few minutes until it turns pale and fluffy. Sift in half the icing sugar and whisk until combined. Sift in the remaining icing sugar and whisk for a good five minutes until the buttercream is soft, pale and fluffy. Add a splash of milk if the buttercream isn’t soft enough
- Put the buttercream into a piping bag with a large round nozzle and set aside until ready to assemble.
- Once the biscuits are cooled and the curd is chilled, pipe some buttercream onto the bottom of one biscuit and spread rhubarb curd onto the bottom of another biscuit. Sandwich the two biscuits together. Use this method to use up all of the biscuits. You should have approximately eight filled biscuits. Place in an airtight container. Biscuits will stay fresh for up to three days.