Preheat oven to 200 C.
Gently press the grated potatoes between paper towels to dry them as best as possible. In a 9-inch pie plate, toss the potatoes and onions with the melted butter, salt and pepper into the plate. Press them into the bottom and up the sides to form a crust. Bake for 30 -35 minutes until golden brown and starting to crisp.
Mean while, in a sauce pan, whisk the whole wheat flour, milk, salt and cayenne pepper. Begin to cook the white sauce, stirring continuously until thickened. Add the baking powder at this stage and whisk until well blended. Turn off heat and add the corn and stir.
When the hash brown/potato crust is ready pour the corn mixture over it, sprinkle the cheese and return to the oven.
Lower the oven temperature to 180 C and bake for about 30 minutes until the quiche is light golden brown on top.
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