1 1/4 cups all purpose flour
1 teaspoon sea salt
1/4 teaspoon coarsely ground black pepper
1/2 cup (1 stick) unsalted butter, cut into pieces, cold
1 large egg yolk
1 tablespoon Dijon mustard
About 2 tablespoons toasted sesame seeds
Optional: 1/2 teaspoon smoked paprika
1/4 teaspoon cayenne pepper or chili powder
Kosher salt for sprinkling
To prepare
Working in the food processor, mix the flour salt and pepper together (plus spices if using.) Add the chunks of butter and pulse until the dough resembles coarse crumbs. Whisk the yolk and the mustard together until blended and drizzle over the flour. Pulse until the dough begins to clump together. Add sesame seeds and pulse two or three times more until barely mixed. Transfer the crumbs to a waxed paper lined clean work surface. With the heel of your hand, push and “slide” the dough to blend until the mixture comes dough. Using a metal dough scraper, lift up about one-third of the dough towards the center and then the other side as if folding a letter. Fold in the ends to form a square. Turn the dough forty-five degrees and repeat the process (pushing/folding) until the dough is blended. Shape the dough into a one-three quarter by twelve inch log (approximately.) Wrap in plastic wrap and refrigerate until firm, over night, or up to two days.
Preheat the oven to 375 degrees F. Line large baking sheets with parchment paper. Using a thin sharp knife cut the log into one-quarter-inch thick slices and place on baking sheets about half an inch apart. Bake until the coins are medium golden on the edges and on the bottom about fifteen minutes. (Rotate the sheets as necessary for even baking.) Sprinkle the crackers with kosher salt when they just come out of the oven… set on rack to cool. When completely cool store in airtight containers. You can free the unbaked logs ahead, wrapped in plastic wrap and then foil for up to one month. Thaw on the counter for an hour, or overnight in refrigerator. Or wrap baked coins and freeze. Refresh them in 325 degrees F. Oven for a few minutes before serving.