¼ pound (1 stick) unsalted butter, at room temperature, plus 2 tablespoons melted
4 ounces freshly grated Parmesan cheese (about 1 cup)
1-1/2 minced fresh lemon thyme leaves, plus 1-2 tablespoons whole leaves for topping crackers
½ teaspoon kosher salt
½ teaspoon freshly ground black pepper
1-1/4 unbleached all- purpose flour
In the bowl of an electric mixer fitted with the paddle attachment, cream butter for 1-2 minutes. With the mixer on low speed, add the Parmesan cheese, thyme, salt and pepper and combine. With the mixer still on low speed, add the flour and combine until the mixture is in large crumbles, about 1 minute. If the dough is too dry, add 1 teaspoon of water.
Dump the dough on a floured surface and press together into a ball and roll it into a 9-inch log. Wrap it in plastic wrap and refrigerate for 30 minutes or up to 4 days. Dough can be frozen at this point (by wrapping further in foil), for 6 months. Defrost in the refrigerator overnight and slice and bake when you are ready to serve the crackers.
Preheat oven to 350 degrees. Cut the log into 3/8-inch-thick slices and place on sheet pan lined with parchment paper. Bake for 22 minutes, until lightly browned, rotating the pan once during baking. Cool slightly, brush the tops of the crackers with melted butter and sprinkle with whole lemon thyme leaves.