• Set oven and line pan. Preheat the oven to 375°F, adjust a rack to the center and line a sheet pan with parchment paper. Set aside.
• Cook onions and garlic with spices. Coat the bottom of a large skillet (approx. 12-inch) with the olive oil and place it over medium-low heat. Add the onion and garlic, and stirring often, sauté just until the onions are soft and translucent, about 7 minutes. Add the nutmeg and cayenne and mix. Set aside to cool.
• Blanch and drain spinach. Bring a large (approx. 6 quart) pot of water to a boil. Add all of the spinach, mix and turn off the heat. Drain as soon as all of the leaves are wilted, about 2 minutes. Leave it in the colander to cool until it’s not too hot to touch.
• Add the Ricotta, 2 tablespoons of the Parmesan, lemon zest, lemon juice, salt and black pepper to a large mixing bowl. Set aside.
• Further drain spinach and mix with eggs. Once you’re able to handle the spinach comfortably, squeeze as much liquid as possible out of it with your hands, one large handful at time. You will likely have close to ¾ cup of liquid, which you can discard. As you do this, add the spinach to a food processor fitted with the blade attachment and add the eggs to it. Blend until it’s relatively smooth and the spinach is in tiny pieces.
• Combine all of the ingredients. Add the spinach mixture, along with the onion mixture, to the bowl with the cheese and mix until it's evenly combined. Set aside.

Assemble

• Lay two pieces of phyllo dough on a clean dry surface and use a pastry brush to brush the top with melted butter. Place two more sheets on top and then brush the surface with more melted butter.
• Use a slotted spoon to scoop about half (about 1¼ cups) of the spinach filling onto the buttered phyllo. With the slotted spoon, allow any liquid that has collected to drip off first. Spread the spinach mixture evenly, leaving a couple of inches of space at both of the short ends. Then gently roll, starting from a short end. (Do not use too much pressure/roll too tightly, or the filling will squeeze out.) Repeat this process with the second half of the filling and phyllo.
• Place the rolls on the parchment-lined sheet pan. Brush both of them with the remaining melted butter. Mix the remaining tablespoon of Parmesan with a pinch of nutmeg and a pinch of cayenne and then evenly sprinkle each roll with it.
• Bake. Bake in the preheated 375°F oven until the phyllo is golden and the filling is cooked through, about 30 minutes.
• Cool and serve. Briefly let them cool, slice each roll in half and serve.