Cookies adapted from Sturbridge Bakery - linked above
Beat the butter and sugar together in a large bowl until light and fluffy. Add in the eggs and vanilla continue to mix.
Add in the flour and salt and mix until combined. It might still be crumbly, but if you put some together with your hand it should form a dough.
Form a disc and wrap it with plastic wrap. Store in the fridge for 1 hour.
Preheat oven to 350. Roll out the dough very thin, between 1/8th and 1/4 inch thin.
Cut the circles, and if you want like mine, you can cut out shapes on half the cookies to form the window effect. I used a straw to make circles cause it was all I had.
Bake on a parchment lined sheet for about 10 minutes until set and just barely threatening to brown on the edges.
Allow to cool for at least 30 minutes. Place about a teaspoon of the jelly on the bottom half, then press the top half on to it. You want the filling to be super thin cause it it VERY bitter and a little goes a long way.
I have not tested freezing these cookies or filling them more than 24 hours before eating