Preheat your oven to 180°C (350°F). Lightly grease your baking dish with butter or oil to prevent sticking.
Heat a teaspoon of oil or butter in a skillet over medium heat. Add the diced onion and cook until translucent, about 3 minutes, filling your kitchen with a sweet aroma.
Add the minced garlic to the skillet and cook for 30 seconds until fragrant, stirring gently to prevent burning.
Stir in the prepared spinach, cooking for another 2-3 minutes until wilted and any excess moisture has evaporated. Remove from heat and let it cool slightly.
In a large bowl, whisk together the eggs and milk until fully blended and slightly frothy. Season with salt, pepper, and a pinch of nutmeg if using.
Fold the sautéed spinach mixture into the egg mixture, then add the grated cheese, gently combining everything to ensure even distribution.
Pour the mixture into the prepared baking dish, spreading it out evenly with a spatula for a uniform top.
Place the dish in the oven and bake for 20-25 minutes, until the top is golden brown and the edges are set. You’ll hear a gentle bubbling and see a lovely color forming.
Check for doneness by inserting a knife or toothpick in the center; it should come out clean, and the top will be puffed and slightly crispy.
Remove from the oven and let rest for 5 minutes. This helps the bake firm up, making it easier to slice and serve.
Slice into wedges and serve warm, garnished with fresh herbs if desired. Enjoy this cozy, customizable breakfast that’s perfect for lazy mornings or brunch.
