Viennese Sandwiches

I recently had a go at making these and it turns out they're really easy and they look super fancy. I don't eat biscuits very often so I make a batch and keep them in a ziploc in the fridge, they keep really well. I also don't like very sweet things so the filling is not the usual one for this kind of biscuit.

There are two things to make sure of: Make sure the butter is very, very soft or you'll struggle to pipe the dough. I've even used melted butter and it's been fine. Also, the piping bag should be cloth, not plastic or silicone. Cloth is stronger and won't split and you can wash it. The silicone ones are crap and split. Plastic, even worse.

Ingredients

For the biscuits

  • 200g slightly salted butter, softened… very soft
  • 50g icing sugar
  • 2 tsp vanilla extract
  • 200g plain flour
  • 2 tsp cornflour
  • ½ tsp baking powder

For the filling

  • 100g slightly salted butter, room temperature
  • 100g dark chocolate
  • 1 tsp vanilla extract
  • ½ tsp instant espresso powder (optional), dissolved in the vanilla

Method

The Biscuits

  1. Making the dough is quick, so heat the oven to 160°C fan and line two baking sheets (I use 40cm by 30cm ones) with baking parchment.
  2. Put the butter and icing sugar in a large bowl and mix them with the spatula. When the sugar is mixed in, beat the mixture with the spatula for a minute or so, this adds a bit of air and helps the texture.
  3. Add the vanilla extract and beat again until fully incorporated.
  4. Sift the flour, cornflour and baking powder onto the butter and sugar mix, and fold in using the spatula until it's just combined.
  5. Put the dough into a piping bag fitted with a large star-shaped nozzle. You can do it in two batches if it doesn't fit.
  6. Pipe the dough into circles about 5cm across, leaving around 2cm between each one. The dough is sticky so weigh the parchment paper down with something or it'll be frustrating.
  7. Bake for 10 minutes, turning the trays around in the oven halfway through. I turn the trays around and swap which shelf they're on so that it's all even. Set a timer for 5 minutes each time or they'll burn.
  8. Let them cool on the tray for 5 minutes, then put them on a wire rack to cool fully.

Filling

  1. Now make the filling. Melt the chocolate! I do this in 30 second bursts in the microwave. You can use whatever method is easiest.
  2. When the chocolate is melted, add the butter, and mix well until it's all mixed in and smooth.
  3. Then add the vanilla and mix it all in again. Let it cool enough so that you can pipe it. It should be similar in gloopiness to mayonnaise.

Assembly

  1. Turn over half the biscuits so the flat side is facing up. Pipe a circle of filling onto each one. You might need a blob in the centre so there isn't a gap.
  2. Combine with the rest of the biscuits to make sandwiches and leave to cool. I do all this on the wire rack and put that in the fridge for an hour, depends on how warm the filling was in the end.

And there you go. They keep for a couple of weeks in an airtight container (I use ziploc bags) in the fridge. I like fridge cold biscuits and the filling is super nice like that.

The kind of chocolate depends on your taste. I don't like things that are very sweet, and I make this with 80% cocoa solids chocolate, I also add the coffee powder to make it more intense.