Instructions
Step 1
In a small skillet, toast the sesame seeds over medium-high heat until golden, stirring occasionally, about 5 minutes. Transfer to a bowl and set aside.
Step 2
In a medium bowl, whisk together the cheese, flour, cayenne pepper, garlic powder, salt, and mustard powder. Add the butter and Worcestershire and use a pastry blender, two forks, or your fingers to incorporate the butter into the flour mixture until pea-sized crumbles form.
Step 3
Transfer the dough to a lightly floured work surface and knead until a stiff dough forms, then roll it into a 2-inch-wide log. Sprinkle sesame seeds onto the work surface and roll the log in the seeds, pressing them into the dough, until completely coated. Wrap the dough in cling wrap and place in the fridge for at least 2 hours, up to 12 hours.
Step 4
Preheat the oven to 350°F. Unwrap the dough and, using a sharp knife, slice it into thin rounds, about ¼-inch thick. Transfer the rounds to a parchment-lined baking sheet, spacing them about 2 inches apart. Bake until the edges are golden, 15-20 minutes. Let the wafers cool completely on the baking sheet and serve. (The wafers will keep in an airtight container for up to five days at room temperature, or up to six months in the freezer.)