Spinach and Cheese Custards
Clean the spinach, rinse well, and place dripping wet in a large pot over medium heat and cook until wilted, about 10 minutes. Drain well, let cool slightly and squeeze the spinach with your hands so to remove the water. Finely chop the spinach.
Peel the onion and chop finely. Heat the oil in a nonstick skillet and toast the pine nuts until golden brown, remove. Add 40 grams (approximately 3 tablespoons) of butter to the pan and saute the onion until translucent. Add the spinach and sauté until piping hot, about 5 minutes. Pour off the excess liquid. Stir in the pine nuts and remove from the heat.
Heat 30 grams (approximately 2 tablespoons) of butter in a pan over low heat and stir in the flour cooking until flour has absorbed all the butter. Gradually add the milk, stirring constantly and bring to a boil over low heat, simmer until thick and smooth, about 10 minutes. Season with salt and remove from heat. Stir in the Grana Padano and the spinach mixture. Whisk the eggs to combine and fold into the mixture.
Preheat the oven to 200°C (approximately 400°F). Butter the serving ramekins and sprinkle with semolina. Fill the ramekins halfway with the spinach mixture, then place 1 well-drained mozzarella ball in the center and cover with the remaining spinach mixture. Place in a single layer in baking dish and hot water to come halfway up the sides of the ramekins. Bake until set, about 30 minutes. Run a metal spatula around the side of the ramekins and invert onto plates, serve warm.