Step 1

Place butter in a small saucepan and melt it. Continue to heat the butter until it turns a pale tan color (making browned butter), but be careful not to burn it. (This takes about 5 minutes.) Remove from heat and cool the butter to just barely warm.

Step 2

Pour the cooled brown butter into a mixing bowl and stir in vanilla and sugar.

Step 3

Combine the flour and baking soda in a separate bowl, and then gradually add to the butter/sugar mixture, stirring until just incorporated.

Step 4

Add in the egg yolk and knead the stiff dough by hand until the yolk is incorporated (alternately, use a stand mixer for the whole process).

Step 5

Preheat the oven to 325 degrees F (160 C) and line baking sheets with parchment paper.

Step 6

To shape lusikkaleivät, take a small portion of dough and press it into a teaspoon. Flatten it off evenly at the top, removing any extra dough as necessary.

Step 7

To remove the shaped cookie from the spoon, either tap gently on the side of the cookie sheet or slide the cookie gently off the spoon with your fingers. They should be placed flat side down on the sheet, with the curved spoon-shaped side up.

Step 8

Bake for 8-10 minutes until just barely browned on the bottom. Remove the cookies from the oven and allow them to cool on the cookie sheets (do not remove to a cooling rack). This ensures they gently cook all the way through without browning too much.

Step 9

Once cooled, spread jam on the flat side of the cookie and sandwich together with a second cookie. They're traditionally rolled in granular sugar at this point, but dusting with powdered sugar (or leaving plain) is also an option.