Mix the dry ingredients, including flour, salt, sugar, cardamom, and baking soda in a bowl. Add 1 tsp of orange zest to the mixture. 

Separate the egg yolks from the white. Save the whites for later, you'll still need them in this recipe.

Mix the yolks with the buttermilk. Add the yolks and buttermilk to the dry ingredients. 

Add the juice from the orange, as well as the melted butter to the dough. If you have a pitcher, add the mixture to it, this makes it easier to pour into the æbleskivejern. Otherwise, let it stay in the bowl. Let the dough rest in the fridge for 30 min. 

Whip the egg whites until they are stiff and fold them into the dough. Beat the first spoonful into the dough. It makes it easier to fold the rest of the egg whites into the dough without losing the air.

Heat your æbleskivejern and put a dab of butter in every hole. You may find that it’s enough to add butter to the holes for the first batch since the dough contains butter. This will depend on your æbleskivejern. If æbleskiver are sticking to the æbleskivejern, then don’t be afraid to add butter before every batch.

Fill each hole ¾ of the way with the dough. 

Turn the æbleskiver when they puff up around the edge and get firmer. Use the bent knitting needle to turn them. You may have to turn them several times to achieve a nice round shape.

Poke the æbleskiver with the knitting needle to see if they are done. If any dough sticks to the needle they aren’t done yet. 

Once a batch is done you can add them to a pan and keep them warm in an oven on low heat. Or you can put them in a dish and cover them with aluminum foil.

Serve the æbleskiver warm with powdered sugar and jam.