Preheat the oven to 375°F (190°C).
Prepare the béchamel sauce if not using store-bought.
Sauté the spinach in a pan until wilted, seasoning with salt and pepper.
Layer half the béchamel sauce in a baking dish, followed by half of the sautéed spinach and diced tomatoes.
Crack three eggs over the first layer and sprinkle with half of the cheese.
Repeat the layering with the remaining béchamel, spinach, tomatoes, eggs, and cheese.
Bake for 25-30 minutes or until the eggs are set and the top is golden.
Let the dish rest for 5 minutes before serving and garnish with fresh herbs.