For the filling, I wanted to do something with jelly. Now I'm really not confident about using gelatine, I usually get it wrong and this time my Sister Bip insisted that I make it vegetarian friendly, so we bought agar flakes to try out.
The cake itself was my usual sponge recipe:
50 g unsalted butter
3 dl plain flour
2 tsp baking powder
2 large eggs
2 dl caster sugar
1 dl single cream
- Pre-heat the oven to 175 °C and butter and four a springform cake tin of 20 cm diameter.
- Melt the butter on low heat and leave to cool.
- Sift together the flour and baking powder.
- In a separate large bowl, whisk together the eggs and sugar until very pale and fluffy.
- Slowly whisk in the flour, alternating with the cream.
- Finally fold in the melted butter, then pour the batter into the cake tin and bake for about 35 minutes.
As it would be a large party, I made two of these, where I sliced a couple of rhubarb stalks lengthwise and placed on top of one of the cakes and sprinkled some caster sugar before baking it.
Once both cakes were baked, I started on the rhubarb. I chose this recipe from the BBC, it seemed nice and simple.
750 g rhubarb stalks
150 g caster sugar
1 dl orange juice
4 dl water
- Trim, wash and dice the rhubarb stalks. Prepare a sieve with double layers of cheese cloth inside it and stand over a bowl.
- Place the rhubarb in a thick-bottomed saucepan together with the sugar, orange juice and water and bring to the boil.
- Simmer for 10 minutes, then strain the mixture, making sure it's all dripped through. You may have to help a bit with a spoon to push it through. Do not discard the remaining rhubarb.
- Measure up the amount of liquid from the rhubarb and work out how many tablespoons of agar flakes are required to set it.
- I wanted two layers of rhubarb jelly, so I divided the liquid into two and made one at a time, following the instructions on the agar flake packet and then pouring into a shallow dish of the right diameter for the cake. I lined it with cling film, to make sure I'd be able to get it out.
- The agar flakes set quite quickly, compared to gelatine, but still allowed enough time to do everything without rushing.
I think the rhubarb jelly set a bit too hard. The packet said to increase the amount of flakes somewhat if setting acidic fruit and I thought rhubarb would be acidic, so I followed this recommendation. What I should have done is to experiment first and make adjustments. But I skipped this because I wasn't sure I'd have enough rhubarb liquid for the two layers.
For the middle filling of the cake, I wanted to use custard, again inspired by the rhubarb tea cake. But I decided to buy ready made fresh custard, rather than make my own. This was quite runny, so I added some agar flakes to set it, but it seems I didn't add enough or they didn't dissolve well or something, because I didn't get the consistency I was aiming for. I wasn't able to find any useful guidance on the internet either.
To make sure the cake wasn't too dry, I made a light sugar syrup.
1¼ parts caster sugar
2 parts water
- Place the sugar and water in a thick-bottomed pan and bring to the boil on low heat. Stir until the sugar dissolves.
- Simmer for 1 minute, then remove from the heat and leave to cool
I cut each of the two cakes in half and as I built up the layers, I brushed a little syrup. Sadly I was worried I'd over-do it and ended up not using enough, so it wasn't noticeable and was quite dry. Must remember to be braver. The term for this is "imbibing" and that should give some indication of the amounts required.
So, bottom sponge, then a layer of the rhubarb jelly, then a second sponge, then the custard, then a third sponge, then another rhubarb jelly, then finally the decorated top sponge.
Sadly the rhubarbs got engulfed during the baking, possibly I should have made them thinner and a bit shorter so they could rise along with the cake surface. I think they got stuck together, so the sponge just rose around them.
Overall the cake didn't look too pretty and didn't taste too nice either, mostly down to the dryness and the texture of the parts. But I think the idea was sound overall.
Now for the remaining squeezed out rhubarb pulp - I had a packet of filo pastry in the freezer and I wanted to try and make what Lundulph terms Rhubarbnik (to match the Bulgarian pumpkin pie tikvenik). And I had custard to spare too.
So I cut the filo pastry into rectangular strips and piped some rhubarb pulp and some custard, then rolled up, brushed with butter and baked until golden brown.
These turned out very nice, but again the custard was just too thin and I couldn't be bothered to try and thicken it either, so it oozed out sadly. I think that perhaps wrapping like samosas might work better here. Or I could have just added more rhubarb to the pulp and made jam again, that usually goes down well.