To a small bowl add: 75g or a ⅓ cup room temperature butter, ¼ teaspoon vanilla powder, the lemon zest, 3 tablespoons whipping cream, and 90g or ½ cup sugar
Whip it up. After it’s pretty well whipped together, add 1 egg and mix it in.
Prepare leavener
Then mix up one tablespoon of lemon juice with ammonium bicarbonate. It should foam.
Add the leavening to the butter mixture. Mix it up.
Make dough
To a small mixing bowl add: 275g or 2 cups cake flour, ¼ teaspoon ground cardamom, and ¼ teaspoon table salt. Mix it up.
Then add the flour mixture to the butter mixture. Mix with a spatula until it comes together.
Dump it on the counter and knead it until you have a cohesive dough.
Put it in a ziplock bag and let it rest in the fridge for about an hour.
Shape klejner
After resting, grab the dough from the fridge and roll it out into a rectangle.
It should be pretty thin—about 2 mm, about ⅛ inch.
Then cut them into rhombus shapes with a pastry wheel cutter. They should be about 3 cm by 8 cm and about 1 inch by 3 inches. Cut a hole in the middle of each rhombus.
Pick one up and stretch the hole a little, then put one end through the hole and tug on it, so it becomes this little knot.
Put them all on a parchment-lined baking sheet.
Cook klejner
After they are all shaped, heat a pot of 1 liter or 4 cups of neutral-tasting oil. It should be 180°C/360°F. I used rapeseed, but you can use peanut, grapeseed, or canola.
Add a couple of klejner at a time, and let them cook on both sides until they are golden brown.
I can fit six klejner at a time in my pot and stagger the timing, so I have some that are halfway done when I add the next batch.
Let them cool on a wire rack with kitchen paper underneath.
They are great when they are still warm but good for a few days after making them.