a double batch of these, made just over 3 dozen
2 sticks salted butter, softened (if unsalted add a little salt)
6 oz cream cheese, softened
1/3 c sugar
1 t vanilla
zest of one Meyer lemon
~3 c flour, plus a bit more for dusting
a few T each of fillings: eg orange marmalade, TJ's blackberry jam, Nutella
Cream together the butter and cream cheese. Beat in the sugar, vanilla, eggs, and zest. Beat in enough flour to make a soft cookie dough. Split in half, wrap each half in plastic wrap, squish into a disc, and stick in the fridge for a couple hours.
Point of interest before you take the dough out of the fridge: there's a fine line between too little flour and the dough sticking to the surface, and too much flour and the corners not sticking together well when you pinch them. To further complicate matters, the location of that fine line depends on how warm the dough is, so what works for one round may not work for the next. I ended up in each of the three regimes at different points (too much flour, too little, and just right) and it was never catastrophic--I still made cookies, and while they may have looked different they tasted exactly the same.
Preheat the oven to 350F. Lightly flour a surface and take the first dough portion out of the fridge. Lightly dust each side of the disc in the flour, lightly flour the rolling pin, and roll out until it's 1/4" thick or maybe a bit thinner. Cut into 3"-diameter circles and put the scraps back on the piece of plastic wrap. Place a teaspoon of filling in the center of each circle, and pinch tightly in three places to make a triangle. Lift each cookie off the surface (which may involve a bit of scraping if you're in the too-little-flour regime) and place on a parchment-lined baking sheet. Repeat with the other portion of dough, mushing the scraps with the first round's scraps and putting the scrap ball (wrapped in plastic) back in the fridge while you fill and pinch the second round. Repeat with the scraps round. Stick in the oven and bake until just barely browning--I wasn't keeping track of the time but the 20 minute recommendation on the link sounds about right. Cool a little bit, and serve to a purim dinner party after challah and shakshuka (scaled up, of course).