Crispy Parmesan Zucchini Potato Muffins

Ingredients:
Makes 12 muffinsCheese

For the Muffins:
1 medium zucchini , grated (about 1 cup)
1 medium russet potato , peeled and grated (about 1 cup)
1/2 cup shredded cheddar cheese
1/4 cup grated Parmesan cheese , divided
1/4 cup all-purpose flour
1 large egg , lightly beaten
2 green onions , finely chopped
1 clove garlic , minced
1/2 tsp salt
1/4 tsp black pepper
1/4 tsp dried oregano (optional, for extra flavor)
For Topping:
2 tbsp melted butter
2 tbsp grated Parmesan cheese
Instructions: