On high speed, whisk egg yolk and sugar until white and thick. Add the vanilla and lemon zest, then the yoghurt and start to add the buttermilk whilst continuously whisking.
Add lemon juice to taste – the soup should be sweet but have a good lemon flavour coming through.
Serve the cold soup in bowls, topped with strawberries and Kammerjunker biscuits.
To make the biscuits/cookies, combine the flour with the baking powder. Add the cold butter, cubed, and mix in until you have grainy consistency. Add the sugar, then the other ingredients and mix again until you have an even dough.
Leave to chill for 20 minutes before rolling the dough.
Turn the oven to 200 degrees C
Roll the dough out and cut 35-40 small pieces, roll them and place on a lined baking tray.
Bake for 7-10 minutes, depending on your oven. Remove from oven and cut each biscuit across the middle so you end up with two flat halves. Return to the warm oven and leave them to finish baking, at 170 degrees, for 8-10 more minutes OR until golden and crisp.
Tip This soup should be eaten on day of making it as it contains raw egg. However, if there’s ever any leftovers at home, I use the this mixed in with a fresh fruit smoothie the morning after: It’s delicious. Recipe is taken from the ScandiKitchen Cookbook by Bronte Aurell, published by Ryland Peter and Small, photography by Pete Cassidy.