To make these fabulously thin Scandinavian wafers, you will need a krumkake iron, which fits over a gas or electric burner. Electric krumkake irons are also available. For a toasted sesame seed effect, a Joy fan suggests sprinkling ¼ teaspoon sesame seeds over the batter each time before closing the iron.

Beat in a medium bowl, or in a stand mixer with the whisk attachment, until light:

Slowly add and beat until pale and the batter falls off the whisk like a glossy ribbon:

Slowly add with the mixer running:

Fold in until well blended:

The batter can be quite variable, so do not add all the flour called for in the recipe to start. Test the batter for consistency by baking one test krumkake. To bake, preheat the krumkake iron over medium-low heat for several minutes, then lightly rub with:

You should not need to grease the iron again unless the krumkakes stick. Use 1 tablespoon batter for each wafer. The batter should spread easily over the whole surface of the iron but not run over the sides when the top is pressed down. If the batter is too thin, add more flour. Should any batter drip over, lift the iron off its frame and cut off the excess batter along the edge with a knife. Cook each wafer until barely browned, about 2 minutes on each side. As soon as you remove it from the iron, roll it up on a wooden spoon handle or cone form, as illustrated. Or you may prefer to leave these cookies flat to use as sandwich cookies; see Stroopwafels.

When cool, fill the cookies (for filling suggestions, see About Curled Cookies).