In a small bowl, combine the oats, quinoa and milk and set aside for 5 to 10 minutes to soften.
In a food processor, combine the flour, baking powder and salt and pulse a few times to blend. 3. Add the cheese and butter and pulse until it forms coarse breadcrumbs.
Add the beaten egg to the softened oats, quinoa and milk and stir to combine. Then add to the food processor and pulse until a dough forms.
Remove the dough from food processor and place onto a sheet of plastic wrap and knead a few times. Form into a disk and wrap it up and refrigerate until firm, about 1 hour.
Preheat the oven to 180 Celsius (355 Fahrenheit) and line 2 baking sheets with baking paper.
Cut the dough in half and work with one half at a time, placing the other in the refrigerator.
Place the dough between 2 sheets of lightly floured baking paper and roll out until ⅛ inch thick.
Cut the dough using cookie cutters and place onto the baking trays and refrigerate while you work on the other piece of dough. Refrigerate the second batch of cut dough for 10 minutes.
Brush the cookies with the egg wash and bake for 15 minutes or until the crackers are golden.