Preheat oven to 325 degrees. Prepare cookie sheet with parchment paper.
In a small saucepan, melt the butter. Continue cooking over medium heat until it begins to brown. Remove from heat and set aside to cool.
Stir sugar, butter, vanilla paste, and egg yolk into butter. Mix well.
Sift together flour and soda, then add to sugar/butter mixture. Stir until a stiff dough forms.
Take a teaspoon and fill with dough. Press the spoon firmly against the side of the bowl and wiggle it until it is filled with dough. Remove the dough from the spoon by sliding it gently off the spoon and onto your fingers. Place on the baking sheet. Repeat until all dough is used. The cookies don't spread much at all, so you can place them quite close together.
Bake for about 10 minutes, until well set. The cookies don't brown much at all. Remove from the oven and cool on cookies sheets. They're very fragile when warm.
Take one cooled cookie, spread with a small amount of jam, then top with a second cookies. Roll the cookie sandwich in granulated sugar in a small bowl.
Store in an airtight container. These actually are better the second day, as the cookies absorb some of the moisture from the jam. This makes them excellent for sending to distant relations.
