Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish or an ovenproof skillet.

Cut the refrigerated biscuit dough into quarters and distribute evenly across the bottom of the prepared dish.

Whisk together 8 large eggs, ½ cup of whole milk, ½ teaspoon of salt, ¼ teaspoon of black pepper, and ½ teaspoon of smoked paprika until fully combined.

Fold in the shredded cheeses, diced bell pepper, chopped onion, and chopped spinach until evenly mixed.

Pour the egg and veggie mixture over the biscuit pieces, pressing down slightly to soak them.

Drizzle melted butter over the top and bake for 25-30 minutes until puffed and golden brown on top.

Let the frittata cool for about 5 minutes before slicing into squares, optionally garnishing with chopped parsley.