1. Preheat the oven to 400°F (200°C) and generously grease a 12 cup muffin pan with olive oil or melted butter to prevent sticking and help the muffins crisp.

2. Grate the potatoes and zucchinis on the large holes of a box grater, then place the shreds in a clean kitchen towel and squeeze firmly over the sink to remove as much liquid as possible.

3. Add the drained potatoes and zucchini to a large mixing bowl, then stir in the grated Parmesan, chopped green onions, garlic powder, salt, and black pepper until evenly combined.

4. Pour in the beaten eggs and sprinkle the flour over the mixture, then mix until everything is well coated and the mixture holds together when pressed in your hand.

5. Divide the mixture evenly among the 12 muffin cups, packing it down firmly with the back of a spoon and mounding the tops slightly to create crispy, frizzled edges.

6. Bake for 22 to 25 minutes, or until the muffins are deeply golden brown around the sides and lightly browned on top.

7. Let the muffins cool in the pan for about 5 minutes, then run a thin knife around the edges to loosen and carefully lift them out.

8. Serve the muffins warm with sour cream, Greek yogurt, or your favorite dipping sauce, or cool completely and store for later.