1/2 cup unsalted butter
1/2 cup sugar
1/2 cup brown sugar

2 eggs
1 teaspoon vanilla extract (if not using vanilla beans)
1 teaspoon almond extract (optional, if you like the flavor, and aren't using the seeds)

Mill together:
    500 grams soft wheat or 400 grams soft wheat plus 100 grams sweet rice
    1 teaspoon mahleb seeds
    2 inches vanilla bean

OR (if you don't mill your own wheat) substitute 3 cups whole wheat pastry flour plus 1/2 cup rice flour OR 3 1.2 cups unbleached all purpose flour
PLUS the vanilla and optional almond extract

1/4 teaspoon salt (omit if using salted butter)
1 teaspoon baking soda
1/2 teaspoon baking powder

Filling

1/2 cup walnuts, ground
1/2 cup poppyseeds, ground (you will need a poppyseed grinder, like this one, or vast reserves of strength, patience, and a mortar & pestle)
2 tablespoons soft butter
1/4 cup powdered sugar
2-3 tablespoons milk

Whisk together the flours, mahleb, salt, baking powder and soda.

Cream the butter and sugar together.  Beat in the eggs and vanilla, if using.

Stir in the flour mixture.  Mix until just holding together smoothly.  It should be a fairly soft dough.  Chill the dough until it is quite firm, several hours in the refrigerator.

While the dough chills, freshly grind the poppyseeds (in a poppyseed grinder) and the walnuts (in a nut grater or your food processor).  Mix with the butter and powdered sugar and just enough milk to make a thick smooth paste.  Chill.  

Preheat the oven to 350 degrees.

Roll the dough out on a floured board 1/8 inch thick.  Cut in 2 inch circles.  Drop a teaspoon of filling on the middle of the circle.  Lift up the edges of the cookie in a tricorner shape, and place on an lightly greased, nonstick or lined baking pan.  

Bake the cookies about 12 minutes, until lightly browned.