I love these cookies; they're not too sweet, that have a lovely crispy-crumbly-buttery texture, and they're made with whole grains. The only way I think that they can be improved upon is by using an egg substitute instead of the egg yolks (but that's just me). Next time I make them I'll use Bob's Red Mill Egg Replacer.
The recipe is from The Essential New York Times Cookbook by Amanda Hesser.
1 cup buckwheat flour
1 cup all-purpose flour
2/3 cup sugar
1/2 teaspoon salt
1/2 teaspoon baking powder
1/2 lb unsalted butter, cut into cubes
2 large egg yolks, beaten
Preheat the oven to 325F. Put the dry ingredients into the bowl of a food processor and pulse once or twice. Add the butter and pulse about 15 times, until pea-sized pieces form. Add the egg yolks and pulse 8 times, just until the dough comes together.
Form tablespoons of dough into balls and place 1 1/2 inches apart on ungreased baking sheets. Use a fork to press the dough into 3/8-inch thick rounds.
Bake for 15 to 20 minutes, until golden around the edges. Cool on a rack.