-
1
Preheat the oven to 350F.
-
2
Put the butter and flour into a food processor, together with the salt, cayenne pepper, mustard powder, and cheeses.
-
3
Briefly process all together to begin with, and then, finally, pulse the mixture in short spurts as you notice the mixture coming together-as pastry, if you like.
-
4
Once the texture is clearly clumpy, tip it all out onto a lightly floured counter and deftly, but thoroughly, knead it together until well blended and smooth.
-
5
Wrap in plastic wrap and chill in the refrigerator for at least 30 minutes.
-
6
Gently roll out the pastry on a lightly floured counter to about an 1/8-inch thickness.
-
7
Using a 1 1/2 to 2-inch cookie cutter, cut out crackers the size you wish for, depending on the occasion.
-
8
Lay them out onto a greased baking tray about 3/4 inch apart; it may be necessary to bake them in 2 batches.
-
9
Carefully brush the surface of each cracker with beaten egg and sprinkle a little finely grated Parmesan over.
-
10
Bake in the oven for 10 minutes, or until a gorgeous, pale golden color is achieved; the superb smell will also inform you that they are ready.
-
11
Carefully lift off the tray using a spatula and place on a cooling rack.
-
12
Serve while still just warm, if possible.
