01 - Preheat the oven to 350°F. Lightly butter four individual ramekins or a medium baking dish.
02 - Heat olive oil in a skillet over medium heat. Add diced onion and cook until translucent, about 2–3 minutes. Add minced garlic and cook for 30 seconds.
03 - Add chopped spinach to the skillet and cook until wilted, about 2 minutes. Season with ground nutmeg, salt, and pepper, then remove from heat and let cool slightly.
04 - Distribute the spinach mixture evenly among the prepared ramekins or spread it in the baking dish.
05 - Sprinkle crumbled feta and half of the shredded cheese over the spinach layer.
06 - Carefully crack one egg into each ramekin or create four wells in the baking dish and place eggs into them.
07 - Drizzle a small amount of heavy cream over each egg and top with the remaining shredded cheese.
08 - Bake in the preheated oven for 15 to 20 minutes, or until egg whites are just set and yolks remain slightly runny.
09 - Remove from oven and allow to rest for 2 minutes before serving.