In the bowl of a food processor place flour, oats, salt, cayenne pepper and dry mustard. Pulse to combine
Add the butter and pulse until mixtures resembles a coarse meal.
Add the cheese and pulse until cheese pieces are finely chopped
With your machine running, slowly add the water and process until the dough holds together
Flatten dough between 2 sheets of wax paper and chill for at least 1 hour
Preheat oven to 350'F
Roll out dough on floured surface to 1/4" thickness and cut with cookie cutter
Transfer to baking sheet and bake for 14 minutes (may need to adjust baking time depending on size of cracker. The 14 minute worked for my 1.5" by 2.5" cutters)
Allow to cool and then store in an air tight container