These mini quiches will keep in the fridge for 1 day ... butter side facing downwards into the muffin cups. Press down lightly so that they are touching the bottom and edges.
Preheat oven to 400 degrees F. Grease 18 muffin tin cups very well with cooking spray. Place 3-4 tablespoons shredded potatoes in each muffin cup and then press firmly along the bottom and sides.